Mozilla

Servo 0.4.0 contains all of the changes we landed in June, which came out to yet another record 558 commits (April: 534, May: 391). For security fixes, see § Security.

servoshell 0.4.0 showing several new features: the ‘width’, ‘height’, ‘device-width’, ‘device-height’, and ‘aspect-ratio’ media query features, plus the upgraded ‘attr()’ function, with a box whose ‘background-color’ and ‘width’ are controlled by data attributes that are in turn set by range inputs

We've shipped several new web platform features:

'attr()', in experimental mode (@Loirooriol, #45041)
'image(<color>)', 'closest-corner', and 'farthest-corner' in 'ellipse()' and 'circle()' (@Loirooriol, #45421)
'calc()' and other mathematical expressions can now be resolved later than parse time, e.g. sign(1em - 32px) (@Loirooriol, #45421)
'font-feature-settings' in '@font-face' (@simonwuelker, #45393)
'@media (device-width)', '@media (device-height)', '@media (height)', '@media (aspect-ratio)', and their min- and max- variants (@jdm, @mrobinson, @nicoburns, @jschwe, #44978, #45707, #45490)
'@media (orientation)' (@nicoburns, #45707)
'@media (pointer)' and '@media (any-pointer)' (@nicoburns, #45681)
'@media (hover)' and '@media (any-hover)' (@nicoburns, #45681)

Plus a bunch of new DOM APIs:

SharedWorker (@Taym95, #45786)
console.dir() (@Taym95, #45109)
customElementRegistry on Document and ShadowRoot (@shubhamg13, #45872)
initialize() on CustomElementRegistry (@shubhamg13, @yezhizhen, #45903)
new CustomElementRegistry() (@shubhamg13, #45791, #45550)
textStream() on Request, Response, and Blob (@yezhizhen, #45864, #45861)
setPointerCapture(), releasePointerCapture(), hasPointerCapture() on Element (@webbeef, #45048)
ontouchstart, ontouchend, ontouchmove, ontouchcancel on Element (@stevennovaryo, #45049)
crypto.subtle.digest() for KT128 and KT256 (@kkoyung, #45699)
crypto.subtle.getPublicKey() for ML-KEM and ML-DSA (@kkoyung, #45252)

This is another big update, so here's an outline:

You can help!

Servo is steadily becoming a bigger and busier project every month, and by June 2026, we've been reading through over four times the commits as we did when we started in September 2023.

line chart showing how many commits landed in Servo’s main repo each month from September 2023 to June 2026 inclusive. there’s a clear linear trend, from 130 commits up to 551 commits

This is hard work, particularly since there are things we need to know that are often difficult to answer just by reading the changes:

Who does the change affect, if anyone? Does it affect users, Servo developers, embedders, or some other group?
What observable difference does the change make, if any?
Does the feature require any preferences to be enabled, or is it enabled for everyone by default?
Are any real-world websites affected by the change?
What issue or broader project is the change related to? This question is answered by Fixes: #xxxxx or Part of: #xxxxx in the PR description.

Thanks to an initiative by @jdm, it's now easier than ever for you to help us answer those questions, using the Servo Highfive bot! If you're working on a pull request that you think might be interesting for the next monthly update, even if you're not 100% sure, tell us about it by following the steps below:

You add the monthly update label to your pull request, or comment @servo-highfive monthly update
Highfive posts a comment asking you some questions
You answer those questions in a comment containing @servo-highfive monthly update answer

Security

Servo's JS runtime, SpiderMonkey 140.10.1, had several security bugs that have been fixed in Servo 0.4.0 with the update to SpiderMonkey 140.11.0 (@jschwe, #45584). For more details, see CVE-2026-8388, CVE-2026-8391, CVE-2026-8974, CVE-2026-8975, and MFSA 2026-48.

Several more security bugs in Servo's JS runtime have been fixed in Servo 0.4.0 with the update to SpiderMonkey 140.12.0 (@jschwe, #45766). The exact CVEs that apply to us are not yet known, but for more details, see MFSA 2026-58.

RSA operations in SubtleCrypto now do modular exponentiation in constant time (@kkoyung, #45631). Please note that our RSA implementation is currently vulnerable to the Marvin Attack - for more details, see RUSTSEC-2023-0071.

ML-DSA operations in SubtleCrypto now do the Decompose step in constant time, fixing RUSTSEC-2025-0144 (@kkoyung, #45294).

We've fixed an HTML injection bug (XSS) in file:/// directory listings, which affected file names containing </script> (@sahvx655-wq, #45510).

Real world compat

Layout correctness has significantly improved on lichess.org, and many websites have become a lot more readable thanks to our improved handling of variable fonts (@simonwuelker, #45768), including Zulip (servo.zulipchat.com) and Speedtest (speedtest.net).

Many websites worked in Servo even before version 0.4.0, including Google Photos (photos.google.com) and Cash Converters (cashconverters.com.au), and continue to work in version 0.4.0. Other websites, like Google Maps (maps.google.com) and OpenStreetMap (www.openstreetmap.org), render well but have some issues with interactivity.

We're interested to hear how well your favourite websites run in Servo! Report successes in this Zulip thread, and failures in our GitHub issues.

Work in progress

We're implementing the more powerful version of 'attr()' that can be used anywhere, not just in 'content', under --pref layout_css_attr_enabled (@Loirooriol, #45041, #45421, #45495, #45752).

WebGPU support has improved, under --pref dom_webgpu_enabled:

implemented copyExternalImageToTexture() on GPUQueue (@sagudev, #45646)
implemented createQuerySet() on GPUDevice and resolveQuerySet() on GPUCommandEncoder (@sagudev, #45644)
implemented pushDebugGroup(), popDebugGroup(), and insertDebugMarker() on GPUCommandEncoder, GPUComputePassEncoder, and GPURenderPassEncoder (@jschwe, #45489)
more conformant GPUTexture (@sagudev, #45300)
more conformant requestAdapter() on GPU (@sagudev, #45424)
more conformant secure context enforcement (@sagudev, #45279)

All of the features above are enabled in servoshell's experimental mode.

We've made more progress towards accessibility support, under --pref accessibility_enabled (@alice, @delan, #45555, #45554, #44949).

We've started implementing visible and interactive text selection (@mrobinson, @SimonSapin, #46107), one of the most long-awaited features of any web browser. Stay tuned!

We've also started working on Web Animations, under --pref dom_web_animations_enabled (@simonwuelker, #45522, #45983), as well as webkitRelativePath on File, under --pref dom_entries_api_enabled (@yezhizhen, #45666).

Rust doesn't have a stable ABI, so it has generally not been possible to embed Servo in another application without building Servo from source. To make it possible, we've started designing a wrapper C API that will let you consume Servo as a prebuilt shared library using the stable and ubiquitous C ABI (@mukilan, #44984). Eventually the idea is that we'll create a wrapper Rust API around that wrapper C API, so you can have both the ergonomics of Rust and the build simplicity of C.

Embedding API

New in the Servo API:

WebView::rendering_context (@mrobinson, #46047)

Breaking changes:

WebView::send_error has been removed (@mukilan, #45502) - this method was always meant to be internal, and has become unused after we introduced the new WebView- and WebViewDelegate-based API

We've improved the docs for WebView, WebViewDelegate, JSValue, AlertDialog, AllowOrDenyRequest, AuthenticationResponse, BluetoothDeviceDescription, ConfirmDialog, ConsoleLogLevel, CreateNewWebViewRequest, EmbedderControl, EmbedderControlResponse, FilePicker, Image, JavaScriptErrorInfo, NavigationRequest, PermissionRequest, PixelFormat, PromptDialog, ProtocolHandlerRegistration, ProtocolHandlerUpdateRegistration, Scroll, SelectElement, SelectElementRequest, and WebViewVector (@mukilan, #45282, #45467).

For users and developers

In servoshell:

the Android version now requires Android 13+ (@jschwe, #46104)
the desktop version now lets you drag and drop files to open them (@simonwuelker, #45454)
the desktop version now lets the tab bar scroll horizontally if you have too many tabs open, but from one tab hoarder to another, maybe you should reconsider having so many tabs open (@Nylme, #44884)
the desktop version enters fullscreen on the monitor containing the window, even if you've moved it to a different monitor (@rhit-kapilaar, #45556)
the desktop UI is more performant, resizes more smoothly, and no longer gets stuck in hovered states (@mrobinson, #45289, #45456, #45290)
<select multiple> should now be interactable on all desktop platforms (@alexcat3, #45419)
localhost:<port> now implies http:// in the location bar and on the command line, rather than treating localhost: as an unsupported URL scheme (@SteveSharonSam, #45729, #45832)

When using the Firefox DevTools:

in the Console tab, uncaught exceptions are reported correctly (@jdm, #45549)
in the Console and Debugger tabs, you can now inspect the elements of nested arrays and the entries of Map objects (@atbrakhi, #45435, #45514, #45767)
in the Debugger tab, the Scopes panel now shows any '(uninitialized)' variables, the value of this, and the global scope (@atbrakhi, @eerii, #45824, #45517)

We've fixed some build issues on riscv32, riscv64, and arm64 (@fxzjshm, @saschanaz, #45285, #45731), and modernised servoshell for Android to use Compose UI and Kotlin (@veyndan, #45923, #45932, #45941, #45982, #45985, #46015, #46035, #46037, #46046, #46053, #46061, #46071, #45641, #45643, #45650, #45665, #45671, #45676, #45679, #45683, #45712, #45713, #45734, #45738).

For developers of Servo itself:

mach try --help now lists all of the kinds of try jobs you can run (@shubhamg13, #45607)
mach test-wpt --update-expectations lets you run Web Platform Tests and update expectations in a single command (@TimvdLippe, #45521), rather than having to run mach test-wpt --log-raw <path> followed by mach update-wpt <path>

More on the web platform

To allow for more performant scrolling, 'wheel' events are no longer .cancelable unless there are one or more non-passive event listeners (@kunalmohan, #45667). Note that like in Firefox, 'wheel' events are passive by default.

'dotted', 'dashed', and 'wavy' text decorations are now continuous across element boundaries (@mrobinson, #45726).

We've improved the conformance of <dialog> (@skyz1, @mrobinson, #45825, #45761), <iframe sandbox> (@cychronex-labs, #45880), <input minlength> and <input maxlength> (@skyz1, #45705), CSS gradients (@mrobinson, #43945), 'font-style' and 'unicode-range' in '@font-face' (@Loirooriol, #45821), FontFaceSet (@mrobinson, #45390, #45382), HTMLInputElement (@steigeo, #45416), IntersectionObserver (@jdm, #45655, #45659, #45680), new Response() (@yezhizhen, #45953), URL.createObjectURL() and URL.revokeObjectURL() (@yezhizhen, #45182, #45417), and ECDSA and Ed25519 in SubtleCrypto (@kkoyung, #45833, #46017).

We've fixed bugs related to <input hidden> (@mrobinson, #45750), 'animation-delay' (@yezhizhen, #45013), 'clip-path' (@Loirooriol, #45468, #45373), 'tab-size' (@SimonSapin, @mrobinson, #45309), 'width' and 'height' (@RichardTjokroutomo, #44627), 'box-shadow: inset' (@Loirooriol, #45620), 'animationiteration' events (@Loirooriol, #45990), 'click' events (@mrobinson, #45751), 'load' events (@jdm, #45883), 'error' events in Worker global scopes (@Gae24, #45829), and document.getElementById() (@mrobinson, #45433).

Garbage collection safety

We use a RefCell-based mechanism to store many of our DOM types in other DOM types, enforcing Rust's "aliasing xor mutability" rule at runtime by panicking if the rule is violated. But when garbage collection happens, we need to borrow() each DomRefCell to trace the references, and this is the source of many panic bugs. To fix that whole class of bugs, we initially created CanGc, a marker type that would annotate the code paths where GC can occur, in conjunction with custom static analysis (@jdm, #33140).

With the Rust type system we can do even better, if we flip that around and require any borrow_mut() call to prove that GC can not occur by passing a NoGC marker value. We can then require that a &NoGC must be borrowed from a &JSContext (which blocks GC) and not a &mut JSContext (which allows GC), taking advantage of how Rust references work without needing any custom static analysis.

We have a large codebase that needs to be migrated in parts, so for now we've created the new method safe_borrow_mut() (@sagudev, #46050). We also need to update all of our script-related code to borrow our safe JSContext wrapper, rather than creating an owned JSContext on the spot.

This continues our long-running effort to use the Rust type system to make Servo's integration with SpiderMonkey safer and more reliable (@Gae24, @Keerti707, @Narfinger, @TimvdLippe, @sagudev, @guptapiyush16, @ivomurrell, @kunalmohan, @skyz1, #45230, #45436, #45503, #45617, #45711, #45797, #45800, #45858, #45884, #45937, #45902, #45968, #45977, #45991, #46003, #46005, #46084, #45548, #45552, #45590, #45909, #45912, #45943, #46089, #46117, #46114, #45320, #45324, #45328, #45340, #45381, #45385, #45410, #45392, #45409, #45604, #45616, #45618, #45627, #45636, #45662, #45663, #45675, #45674, #45677, #45684, #45735, #45807, #45810, #45816, #45818, #45828, #45838, #45836, #45837, #45840, #45841, #45857, #45859, #45862, #45875, #45887, #45931, #45964, #45935, #45987, #45988, #46001, #46040, #46051, #46057, #46106, #46125, #45678, #46002, #45845, #45645, #45673, #45259, #45817, #45822, #45876, #45877, #45891).

Performance and stability

NoGC was designed to prevent dynamic borrow failures, but it also enables some performance optimisations! If we can prove that garbage collection is impossible in some part of Servo, we can often avoid rooting JavaScript objects when interacting with them within that region of code. This has allowed us to reduce overheads by over 1% in the layout process and in HTMLCollection (@Narfinger, #46092, #45582).

Our memory usage has improved, with BoxFragment now 17% smaller (288 → 240 bytes on amd64) and ShapeCacheEntry now smaller too (@SimonSapin, @mrobinson, @simonwuelker, #45183, #45496).

We've fixed some nasty memory leaks when reloading and in 2D canvases (@Taym95, @sagudev, @jschwe, #45455, #45261, #45414).

Speaking of which, 2D canvases now use up to 23% less power (@yezhizhen, #45301), and we now avoid rasterising the same SVG more than once (@Narfinger, @jschwe, #44805).

Servo now decodes all images asynchronously and fills image caches asynchronously, leaving script threads (web content processes) more time for other work (@Narfinger, #45542, #44483). On top of that, we've improved incremental layout (@mrobinson, @Loirooriol, #45411) and reduced reflows in IntersectionObserver (@jschwe, #45986).

We've started working on incremental updates for the stacking context tree, and as a side effect, we've made some layout-bound microbenchmarks up to 10% faster (@mrobinson, @Loirooriol, #45208).

We've also reduced allocations, copies, GC rooting steps, and other operations in many parts of Servo (@Narfinger, @SimonSapin, @mrobinson, @Loirooriol, #45506, #45969, #45940, #45760, #46090, #45335, #45413, #45511).

For several months, Frédéric (@fred-wang) has been fuzzing for Servo bugs, and thanks to his work we've fixed sixteen (16) crash bugs in June, affecting <iframe>, <slot>, <link onerror>, 'animation', 'clip-path', 'content', 'rotate', 'transition', 'transform-style', 'display: contents', 'overflow: clip', CSSKeyframesRule, FontFace, stop() on Window, document.elementFromPoint(), and the DOM tree (@mrobinson, @Loirooriol, @fred-wang, #46031, #46027, #46054, #46058, #46016, #46028, #46033, #45287, #45951, #45634, #45629, #46110, #46094, #45799, #45611, #45682, #45788, #45612, #45834).

We've also fixed crash bugs related to IPC failures, HTMLInputElement, Range, the DevTools Debugger tab, and when servoshell is built with --features native-bluetooth (@jschwe, @Taym95, @mrobinson, @atbrakhi, @mukilan, #45311, #45619, #45765, #45513, #45702).

New contributors

A special thanks to the following people for landing their first patch in Servo:

Deepam Goyal (@Deepam02, #44836)
Mark (@Mark-Boger, #45486)
Mr SheerLuck (@MrSheerluck, #45557)
Psychpsyo (Cameron) (@Psychpsyo, #45494)
TusharSariya (@TusharSariya, #43663)
Adam Sharif (@adamsharifc, #45551)
Akash Ravikumar (@ak4shravikumar, #45736)
Sean Cunneen (@alexcat3, #45419)
Abdul Wahab Melethil Shibu (@cychronex-labs, #45880)
darkdragon-001 (@darkdragon-001, #45267)
Frédéric Wang Nélar (@fred-wang, #45834)
fxzjshm (@fxzjshm, #45285)
Piyush Gupta (@guptapiyush16, #45845)
Ivo Murrell (@ivomurrell, #45645)
rhit-kapilaar (@rhit-kapilaar, #45556)
sahvx655-wq (@sahvx655-wq, #45510)
Kagami Sascha Rosylight (@saschanaz, #45731)
shangguanmachine-dot (@shangguanmachine-dot, #45310)
Glenn Skrzypczak (@skyz1, #45471)
Oskar Steiger (@steigeo, #45416)
Veyndan Stuart (@veyndan, #45326)

Interested in helping build a web browser? Take a look at our curated list of issues that are good for new contributors!

Donations

Thanks again for your generous support! We are now receiving 7681 USD/month (+0.2% from May) in recurring donations. This helps us cover the cost of our speedy CI and benchmarking servers, one of our latest Outreachy interns, and funding maintainer work that helps more people contribute to Servo.

Servo is also on thanks.dev, and already 35 GitHub users (same as May) that depend on Servo are sponsoring us there. If you use Servo libraries like url, html5ever, selectors, or cssparser, signing up for thanks.dev could be a good way for you (or your employer) to give back to the community.

We now have sponsorship tiers that allow you or your organisation to donate to the Servo project with public acknowlegement of your support. If you're interested in this kind of sponsorship, please contact us at join@servo.org.

7681 USD/month

10000

Use of donations is decided transparently via the Technical Steering Committee's public funding request process, and active proposals are tracked in servo/project#187. For more details, head to our Sponsorship page.

31 Jul 2026 12:00am GMT

Thunderbird Mobile is moving forward with large steps on both platforms we support. On iOS, we're working on the very foundation of a new app-our first built from scratch-and continuing to make progress in bringing the Thunderbird for iOS app to the App Store. For Android, it's a matter of updating what we have in place to make it easier to use, more reliable, and more efficient. Both platforms are rushing forward to deliver exactly what our users expect from us.

iOS

Starting off with iOS, we've focused on a few vital components. This includes the compose screen, account drawer, and OAuth, which allows users to add their accounts using the sign in page of their email provider. For the compose view, our HTML rich text editor is coming along nicely. We forked a WYSIWYG repository, Infomaniak's "swift-rich-html-editor," to create a rich text view for both composing and editing. We also added view headers, fixed a bug where we weren't applying links properly to the DOM, and began porting a proof of concept over to the main app code. This will eventually become the compose view for the final app. We also started the technical design phase for the new account drawer design.

Android

The Android team has been busy looking into drastic changes to the app to make it more user-friendly, faster, and more reliable. We're directly targeting feedback we've received. We're also continuing work on developer-friendly features to make contributing to the project easier and faster.

Database Rewrite

We've started our large database refactor with a tentative selection of Room. We chose this for a number of reasons, including performance, easier writing of data entities, and the ease of introduction for new engineers. Room is common in Android development, which means we can more quickly onboard new contributors with it. We'll have an RFC out by the end of August detailing how we'll implement the new database.

So why are we rewriting the database? It's the source of a number of issues with the app. Everything runs through it, from fetching locally-stored drafts, triggering notifications for new messages, syncing, reliability, and even power consumption. By updating the database, we make it possible to drastically improve everything in the app it touches, which is to say, everything.

Feature Flags

Developers will also be happy to know we're improving the feature flag process. We've completed an RFC for a new schema and began work on the technical documentation. We're looking to develop a local feature flag library that will use OpenFeature and eventually enable remote feature flag management, though that's not our short term goal. For now, we want to make it easier to create and modify feature flags across build types, without needing to edit so many files to do so. In the future, however, this will make it easier for us to roll out releases, updated features, and even rolling back features that may have issues without having to wait for the app release and approval cycle. It allows us to make a more reliable app with faster feature implementations.

Notifications

Finally, we've heard that our users do not like how we handle notifications. We've been investigating reported bugs and working to find a path forward that allows us to use previous work to improve notifications.

We're also looking into a key complaint: setting up notifications and "push" (IMAP Idle) notifications is just too difficult. We don't make it easy enough for users to set up their notifications and ensure they get email notifications when their email server reports updates. Users have made it clear: that has to change.

We're currently discussing options with design to consolidate some settings, bring other settings to the forefront, and will be working next month to activate "push" notifications by default for new accounts that support it.

We know notifications are a cause of headaches, even for those who understand how to use the app's existing features, so we want to address them as quickly as possible. We'll also focus on identifying issues and helping our users report problems with notifications in detail with user-enabled and anonymous logging that can help us see why a notification did not show for a new email if they want to help us work through it.

Bolt Design Library

Android has also begun the work of moving our Bolt design library out of the app to serve as a standalone library. Currently, we've pulled out the foundation layer for mobile that includes fonts, colors, spacing, and other repeated values. Eventually we'll use WebASM to render the design system and allow contributions directly to the design system, without needing to touch the Android app, potentially allowing it to be platform independent.

Community

Two crashes were caught in the beta, including a crash related to relative date formats and another to webviews. We want to thank our amazing community of beta testers who helped us catch these before they made it to a full release. Our community contributors have also directly fixed bugs, like issues scrolling horizontally in message views, fixing a button that couldn't be seen properly in dark mode, fixing an issue with the wrong number of messages in confirmation dialogs, and updates to our historical changelog data to be in a more readable and usable format. We can't thank our community of testers, contributors, and users enough for the work they put in helping us make Thunderbird a better email client.

We couldn't do what we do without you, and, as always, thank you for being part of the Thunderbird community. Here's to another month making the best email client we can, together!

- Danielle G. (she/her), Senior Android Engineer

The post Mobile Progress Report: July 2026 appeared first on The Thunderbird Blog.

30 Jul 2026 7:00pm GMT

Firefox keeps evolving, and the community continues to play a big part in shaping what's next.

In this edition, you can get an early look at Project Nova through our latest foxfooding opportunity, explore Tab Groups on Android, join the conversation on Mozilla's latest browser choice research, and meet an Outreachy contributor whose journey reminds us why open source thrives through collaboration.

Get ready to dive in!

Hot from the oven: Join Project Nova foxfooding

We teased it in the last edition, and now it's here. Project Nova has finally arrived on Firefox Nightly, and you're invited to be an early tester! Get a look at Firefox's refreshed design as we put the finishing touches on the experience ahead of its broader release later this year. If you're curious about what's coming next, this is your chance to try it out, share your feedback, and help shape the final product.

Learn more

Monthly Community Call today!

Want to ask questions directly to the people working on Firefox? Join us for today's Monthly Community Call, where we'll discuss Project Nova and Firefox performance feature with members of the teams working on these projects. Join the call today, July 29, 2026, at 5:00 PM UTC, and bring your questions!

Watch our livestream

Tab groups arrives on Android

You've been calling out for tab group functionality on Firefox mobile and now Tab Groups have officially arrived on Firefox for Android! Tab Groups make it easier to organize related tabs into color-coded groups for work, travel, shopping, research, or whatever you're browsing. Give it a try, and if you have ideas for how it could be even better, let us know on Mozilla Connect.

Updates from Rust Community

Newsletters

Scientific Computing in Rust #20 (July 2026)

Project/Tooling Updates

Observations/Thoughts

Rust Walkthroughs

No Tokens Yet Does Not Mean a Rust LLM Stream Is Safe to Retry
[series] Rama 101.2: Core Concepts
[video] [series] What's Inside Axum?

Crate of the Week

This week's crate is cargo-efmt, a drop-in replacement for cargo fmt to support .editorconfig.

Thanks to kleines Filmröllchen for the self-suggestion!

Please submit your suggestions and votes for next week!

Calls for Testing

An important step for RFC implementation is for people to experiment with the implementation and give feedback, especially before stabilization.

If you are a feature implementer and would like your RFC to appear in this list, add a call-for-testing label to your RFC along with a comment providing testing instructions and/or guidance on which aspect(s) of the feature need testing.

No calls for testing were issued this week by Rust, Cargo, Rustup or Rust language RFCs.

Let us know if you would like your feature to be tracked as a part of this list.

Call for Participation; projects and speakers

CFP - Projects

Always wanted to contribute to open-source projects but did not know where to start? Every week we highlight some tasks from the Rust community for you to pick and get started!

Some of these tasks may also have mentors available, visit the task page for more information.

No Calls for participation were submitted this week.

If you are a Rust project owner and are looking for contributors, please submit tasks here or through a PR to TWiR or by reaching out on Bluesky or Mastodon!

CFP - Events

Are you a new or experienced speaker looking for a place to share something cool? This section highlights events that are being planned and are accepting submissions to join their event as a speaker.

No Calls for papers or presentations were submitted this week.

If you are an event organizer hoping to expand the reach of your event, please submit a link to the website through a PR to TWiR or by reaching out on Bluesky or Mastodon!

Updates from the Rust Project

570 pull requests were merged in the last week

Compiler

Library

Cargo

Rustfmt

Rustdoc

Clippy

Rust-Analyzer

Rust Compiler Performance Triage

Several large improvements landed in the past week:

rustdoc is on average roughly 16% faster across all of our doc benchmarks:
rustdoc: Only inline impls for local primitives, 7% faster doc builds
rustdoc: Only synthesize auto/blanket impls for documented items, another 7% faster doc builds
rustdoc: Only build extern trait impls if needed, another 10% faster doc builds
Early removal of no-op panic handling in debug builds. This speeds up Cargo by ~4% in cycle count.
Optimize escape_string_symbol() sped up large include_bytes!/include_str! through changes to string escaping, avoiding a regression in upcoming LLVM 23 upgrade.

Great to see so many improvements!

Triage done by @simulacrum. Revision range: d527bc9b..ad0c9dce

Full report here

Approved RFCs

Changes to Rust follow the Rust RFC (request for comments) process. These are the RFCs that were approved for implementation this week:

No RFCs were approved this week.

Final Comment Period

Every week, the team announces the 'final comment period' for RFCs and key PRs which are reaching a decision. Express your opinions now.

Tracking Issues & PRs

Rust

Compiler Team (MCPs only)

Rust RFCs

Cargo

No Items entered Final Comment Period this week for Language Reference, Language Team, Leadership Council or Unsafe Code Guidelines. Let us know if you would like your PRs, Tracking Issues or RFCs to be tracked as a part of this list.

New and Updated RFCs

RFC: Externref lang item for Wasm targets

Upcoming Events

Rusty Events between 2026-07-29 - 2026-08-26 🦀

South America

2026-08-08 | São Paulo, SP | Rust-SP
- Rust SP - Aug/2026

If you are running a Rust event please add it to the calendar to get it mentioned here. Please remember to add a link to the event too. Email the Rust Community Team for access.

Jobs

Please see the latest Who's Hiring thread on r/rust

Quote of the Week

So let's talk about what the process has looked like for Netstack3. For 11 months, the team has been ramping up a dogfooding program. At peak, that program has seen about 60 devices running nearly 24/7 in developers' homes.

Again, if this were any other netstack, we would have expected to uncover a giant mountain of bugs in that time. So, over the past year, how many bugs did the team uncover in the field?

Three.

- Josh Liebow-Feeser on his blog

llogiq again has no one to thank for a suggestion, so he is thankful to himself for finding this quote instead.

Please submit quotes and vote for next week!

This Week in Rust is edited by:

Email list hosting is sponsored by The Rust Foundation

Discuss on r/rust

29 Jul 2026 4:00am GMT

Bugs resolved in Moz-Phab 2.15.4:

bug 2058150 moz-phab patch crashes with KeyError when a stack relative is not visible to the user

Discuss these changes in #engineering-workflow on Slack or #Conduit Matrix.

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27 Jul 2026 4:15pm GMT

This past May, we shared our vision for the future of Firefox. Starting today, you can try out the next design evolution of Firefox in Nightly.

It's still Firefox, now with a more cohesive look and feel across tabs, menus, panels, and other browser surfaces. You'll notice softer tab shapes, a warmer color palette, updated icons, and - after hearing from many of you - the return of Compact Mode and new theme options to make Firefox your own.

Many of you have already spotted pieces of the new design in Nightly over the past few months. Now they're coming together into one complete experience.

You'll continue to see updates over the coming weeks as we polish the new Firefox design before it reaches Firefox users more broadly later this year. As you browse, we're especially interested in any visual or functional issues you encounter.

Keep an eye out for things like:

Icons, spacing, and alignment
Themes and personalization
Different window sizes and display scaling
Keyboard navigation
Screen readers and other accessibility features
Different languages and layouts

Found a bug?

If something doesn't look or behave as expected, please file a bug in Bugzilla.

When possible, include:

Steps to reproduce the issue
Screenshots or screen recordings
Your operating system and Nightly version

If you have broader thoughts or questions about your experience, join the discussion on Mozilla Connect.

Thanks for using Nightly and helping us improve Firefox. Every bug report helps us identify issues and continue refining the new Firefox design before it reaches Firefox users more broadly later this year.

27 Jul 2026 3:00pm GMT

The following changes have been pushed to bugzilla.mozilla.org:

Github Link

Bug 2055236 - The column headers in Github PR are barely visible in dark mode
Bug 2054574 - Do not auto-assigning Hackbot when submitting a Phabricator revision

Github Link

The following changes have been pushed to bugzilla.mozilla.org:

Bug 2055285 - Remove the "Show closed/merged PR" checkbox in the GH PR view

Discuss these changes in the BMO Matrix Room

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23 Jul 2026 10:34pm GMT

We had a bumper release of WebExtensions API updates in Firefox 153. To start, there is a permissions change that affects how your extensions access local files. We then have two contributions from the community members: userScripts.execute() and the new publicSuffix API. We're covering those contributions in more depth, including the people behind them, in a separate post. And there is more, read on…

File access now requires a dedicated permission

Extensions that need to read file:// URLs used to get that access as part of the "Access your data for all websites" host permission. Starting in Firefox 153, file access is a separate, explicit permission, "Access local files on your computer", shown in the extension's permissions settings. It's off by default for every extension, including ones already installed.

This change has a few concrete effects on code:

Before: an extension with <all_urls> or a matching host permission could read file:// pages without any additional grant, and extension.isAllowedFileSchemeAccess() always returned false regardless of the permission setting.
After: the extension must have the new file-access permission granted, and extension.isAllowedFileSchemeAccess() correctly reflects whether the user has granted it.

async function checkFileSchemeAccess() {
  const isAllowed = await browser.extension.isAllowedFileSchemeAccess();

  if (!isAllowed) {
    await browser.notifications.create("file-scheme-access-needed", {
      type: "basic",
      iconUrl: browser.runtime.getURL("icons/icon-48.png"),
      title: "Local file access required",
      message:
        'This extension needs "Allow access to file URLs" enabled to work ' +
        "with local files. Go to about:addons → select this extension → " +
        "turn on that setting, then reload the page.",
    });
    return false;
  }

  return true;
}

devtools.inspectedWindow.eval() calls targeting file:// URLs are affected the same way; they now require this permission to succeed.

If your extension depends on file:// access, expect existing users to see that access stops after upgrading (until they enable the permission), and consider adding a prompt or fallback path, for example by specifying an embedded options page (options_ui) and calling browser.runtime.openOptionsPage() to open about:addons and including instructions to toggle the setting in the "Permissions and data" tab.

userScripts.execute() and publicSuffix: covered in our next post

Firefox 153 adds two community-contributed APIs:

userScripts.execute(), which provides for one-off injection of one or more user script sources into a tab or frame, in a defined order, as a complement to the persistent, URL-pattern-based userScripts.register().
publicSuffix, which enables synchronous lookups against the browser's built-in Public Suffix List using publicSuffix.isKnownSuffix(), publicSuffix.getKnownSuffix(), and publicSuffix.getDomain(). This API means that extensions no longer need to bundle or maintain a suffix list to determine a hostname's registrable domain (eTLD+1).

Both APIs were built by contributors motivated by real needs in their extensions. We take an in-depth look at these contributions, their developers, impact, and history in a forthcoming post.

documentId support across more APIs

Firefox 153 introduces documentId, a stable identifier for a document instance, including a new runtime.getDocumentId() method, several webNavigation events and methods, webRequest events, scripting injection targets, and the extension messaging APIs.

Many WebExtension APIs use tabId and frameId to identify where to perform an operation. However, because frameId identifies the frame rather than its content, the loaded document can change and the extension's subsequent operation ends up targeting the new (intended) document. documentId addresses this problem by providing a unique ID for the document. Now, if an extension uses the ID and the frame's document has changed, the operation fails rather than silently targeting the wrong document.

See Work with documentId for the full list of supported events and methods, along with guidance on using it.

Content scripts can read and modify adopted stylesheets

Content scripts can now access document.adoptedStyleSheets and ShadowRoot.adoptedStyleSheets directly.

const sheet = new CSSStyleSheet();
sheet.replaceSync("* { background: pink; }");
document.adoptedStyleSheets = [sheet];

This enables extensions to inspect or modify constructed stylesheets from a content script, without using .wrappedJSObject, a workaround that risks interference from the web page.

Theme manifest key: gradients in additional backgrounds

The theme manifest key's images.additional_backgrounds property now accepts CSS gradients alongside image URLs. A new properties.additional_backgrounds_size property controls the size of each additional background item.

Contextual identities (containers)

If your extension supports contextual identities, you now have access to two new methods: contextualIdentities.getSupportedColors() and contextualIdentities.getSupportedIcons(). These methods return the supported colors and icons, so your extension doesn't need to hardcode either list.

Also, the colors have been updated to align with the new UI theme: "turquoise" is now "cyan", "toolbar" is now "gray", and "violet" has been added. The old names still work for backward compatibility, but your extension should switch to using getSupportedColors() rather than hardcoding either the old or new names.

Add a build-for-amo script

While this isn't about new APIs, I wanted to mention a change that's part of our work to make source code review faster and more reliable. When you submit an extension version, AMO now attempts to build your extensions from the submitted source code and compares the result to the package you uploaded. When the two match, reviewers don't have to verify the build manually. This means submission can move through its review faster.

For now, this applies only if you submit source code that includes a package.json file to build your extension. If your extension has no build step, or you use a different build system, nothing changes. The AMO builder keeps its zero-config approach.

So, if your extension's source code uses a package.json file, add an npm script named build-for-amo that runs the commands needed to build your extension for Firefox:

{
  "scripts": {
    "fx-build": "some commands to build your add-on for Firefox",
    "build-for-amo": "npm run fx-build"
  }
}

If you've a Firefox-specific build command, just point build-for-amo at it. When present, the builder invokes this script instead of guessing how to build your extension. And while you are at it, make sure all your dev dependencies are listed in the package.json file.

For more information, including documentation and Bugzilla links, see the Changes for add-on developers section of the Firefox 153 for developers release notes on MDN.

As always, file extension-related issues on Bugzilla under the WebExtensions product, cross-browser API proposals are discussed in the W3C WebExtensions Community Group, and questions are welcome on the Add-ons Discourse.

The post Firefox 153 WebExtensions API updates appeared first on Mozilla Add-ons Community Blog.

23 Jul 2026 11:35am GMT

As we head into the summer months, a new Extended Support Release (ESR) is in full bloom. Thunderbird 153 "Meadow" is out now, and from all of us at MZLA, the Thunderbird Council, and our global community of contributors, we can't wait for you to try it out.

"Meadow" builds on Thunderbird 140 "Eclipse," along with the steady stream of features and improvements that have landed in the Monthly Release channel over the past year. This release makes first-time setup smoother with a redesigned Account Hub, brings native Microsoft Exchange support out into the open, and lets Thunderbird take on the colors of your desktop. Add privacy-minded networking, friendlier notifications, and a healthy crop of refinements, and Meadow is ready to grow with you.

Easier Account Creation

The all-new Account Hub makes setting up accounts faster and more intuitive than ever, with improved autodiscover, automatic protocol detection, and automatic setup of connected calendars and address books.

Address Book Setup

The new Account Hub modal lets you set up all types of local and remote address books. Existing email accounts are automatically scanned to detect available address books that haven't been configured yet.

Microsoft Exchange Support

We've added full support for Exchange email servers via Exchange Web Services: set up Microsoft Exchange accounts natively to read, manage, and write emails, no add-ons required. Experimental Microsoft Graph support is already in core but temporarily disabled behind a preference while we finish it, with full support plus Calendar and Address Book integration aimed for later this year.

Accent Colors

Meadow now inherits your operating system's accent color to match your preferred look. You can also customize your colors with the new accent color settings in the Appearance tab.

Do More From Your Notifications

Mark an email as read, delete it, flag it as spam, and more right from the native notifications on your operating system.

In addition to these headline features, there's a whole host of other updates you'll love, including:

OAuth in Browser

Thunderbird now supports OAuth authentication directly in your default browser.

Login With Thundermail

If you have a Thundermail account, you can sign in to Thunderbird with one-click authentication in the Account Hub.

Folder Sorting

An improved UI and better visual indicators make sorting your emails easier than ever.

Bug Fixes and Improvements

Thousands of bug fixes and performance improvements bring you the smooth, reliable Thunderbird experience you expect.

Looking Forward

Thunderbird 153 "Meadow" might seem soothing and calm, but we're excited to get these features into your hands. And if you'd like updates like these more often, there's no need to wait for the annual release: switching to Thunderbird Release gets you new updates on a monthly basis.

Thunderbird 153 Availability for Windows, Linux, and macOS

Even with QA and beta testing, any major software release may have issues that only surface after significant public use. That's why we're rolling out automatic updates gradually, enabling them more broadly as we confirm everything is stable.

Manual upgrade to 153 is now enabled via Help > About - you can upgrade now or wait to receive automatic updates. Thunderbird 153.0 is also offered as a direct download from thunderbird.net. Be sure to select 'Thunderbird Extended Support Release' in the 'Release Channel' drop-down menu.

For Linux users running Thunderbird from the Snap or Flatpak, 153 will be available within the next few weeks. Likewise, Thunderbird 153 will arrive on the Microsoft Store by mid-July.

Full r elease notes can be found he re.

If you have any issues, please reach out to support.

Have an idea? We want to hear it! Submit your ideas here.

The post Thunderbird 153 "Meadow" is out now! appeared first on The Thunderbird Blog.

22 Jul 2026 9:45pm GMT

The latest version of PerfCompare is now live!

Check out the change-log below to see the updates:

[kala-moz]

[moijes]

Bug 1986319: Auto-select for partial or full hash matches (#1066 )

[sumairq]

Bug-1855186 : Show whether lower or higher is "better" for each metric (#1051 )

Thank you for the contributions!

Bugs or feature requests can be filed on Bugzilla. The team can also be found on the #perfcompare channel on Element. Come and chat!

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22 Jul 2026 5:36pm GMT

Hello and welcome to another issue of This Week in Rust! Rust is a programming language empowering everyone to build reliable and efficient software. This is a weekly summary of its progress and community. Want something mentioned? Tag us at @thisweekinrust.bsky.social on Bluesky or @ThisWeekinRust on mastodon.social, or send us a pull request. Want to get involved? We love contributions.

This Week in Rust is openly developed on GitHub and archives can be viewed at this-week-in-rust.org. If you find any errors in this week's issue, please submit a PR.

Want TWIR in your inbox? Subscribe here.

Updates from Rust Community

Official

Announcing Rust 1.97.1

Newsletters

The Embedded Rustacean Issue #76

Project/Tooling Updates

Observations/Thoughts

Rust Walkthroughs

Crate of the Week

This week's crate is xan, a TUI toolkit to work with CSV files.

Thanks to Simeon H.K. Fitch for the suggestion!

Please submit your suggestions and votes for next week!

Calls for Testing

An important step for RFC implementation is for people to experiment with the implementation and give feedback, especially before stabilization.

If you are a feature implementer and would like your RFC to appear in this list, add a call-for-testing label to your RFC along with a comment providing testing instructions and/or guidance on which aspect(s) of the feature need testing.

No calls for testing were issued this week by Rust, Cargo, Rustup or Rust language RFCs.

Let us know if you would like your feature to be tracked as a part of this list.

Call for Participation; projects and speakers

CFP - Projects

Always wanted to contribute to open-source projects but did not know where to start? Every week we highlight some tasks from the Rust community for you to pick and get started!

Some of these tasks may also have mentors available, visit the task page for more information.

No Calls for participation were submitted this week.

If you are a Rust project owner and are looking for contributors, please submit tasks here or through a PR to TWiR or by reaching out on Bluesky or Mastodon!

CFP - Events

Are you a new or experienced speaker looking for a place to share something cool? This section highlights events that are being planned and are accepting submissions to join their event as a speaker.

No Calls for papers or presentations were submitted this week.

If you are an event organizer hoping to expand the reach of your event, please submit a link to the website through a PR to TWiR or by reaching out on Bluesky or Mastodon!

Updates from the Rust Project

576 pull requests were merged in the last week

Compiler

Library

Cargo

Rustdoc

Clippy

Rust-Analyzer

Rust Compiler Performance Triage

The two most notable changes this week were #159115, which resulted in pretty nice instruction count wins for full incremental builds on several benchmarks, and #159091, which enabled PGO for rustdoc, which makes it ~3-4% faster across the board.

There were two large rollups with tiny performance regressions, which made it difficult to find the offending PRs.

Triage done by @Kobzol. Revision range: 5503df87..d527bc9b

Summary:

(instructions:u)	mean	range	count
Regressions ❌ (primary)	0.4%	[0.2%, 1.0%]	40
Regressions ❌ (secondary)	0.7%	[0.2%, 4.6%]	69
Improvements ✅ (primary)	-2.0%	[-6.2%, -0.2%]	136
Improvements ✅ (secondary)	-2.6%	[-8.4%, -0.2%]	119
All ❌✅ (primary)	-1.4%	[-6.2%, 1.0%]	176

2 Regressions, 3 Improvements, 6 Mixed; 4 of them in rollups 34 artifact comparisons made in total

Full report here.

Approved RFCs

Changes to Rust follow the Rust RFC (request for comments) process. These are the RFCs that were approved for implementation this week:

No RFCs were approved this week.

Final Comment Period

Every week, the team announces the 'final comment period' for RFCs and key PRs which are reaching a decision. Express your opinions now.

Tracking Issues & PRs

Rust

Compiler Team (MCPs only)

Leadership Council

Deallocate post-2026 funds from PM and compiler-ops

Unsafe Code Guidelines

Do the bytes of a pointer have to stay in the same order?

No Items entered Final Comment Period this week for Cargo, Language Reference, Language Team or Rust RFCs.

Let us know if you would like your PRs, Tracking Issues or RFCs to be tracked as a part of this list.

New and Updated RFCs

RFC: Refactor the libs team

Upcoming Events

Rusty Events between 2026-07-22 - 2026-08-19 🦀

Virtual

2026-07-24 | Virtual (Girona, ES) | Rust Girona
- Sessió setmanal de codificació / Weekly coding session
2026-07-28 | Virtual (Dallas, TX, US) | Dallas Rust User Meetup
- Fourth Tuesday
2026-07-28 | Virtual (Washington, DC, US) | Rust DC
- Mid-month Rustful
2026-07-30 | Virtual (Berlin, DE) | Rust Berlin
- Rust Hack and Learn
2026-07-31 | Virtual (Girona, ES) | Rust Girona
- Sessió setmanal de codificació / Weekly coding session
2026-08-01 | Virtual (Kampala, UG) | Rust Circle Meetup
- Rust Circle Meetup
2026-08-02 | Virtual (Dallas, TX, US) | Dallas Rust User Meetup
- Rust Deep Learning: First Sunday
2026-08-04 | Virtual (London, UK) | Women in Rust
- 👋 Community Catch Up
2026-08-05 | Virtual (Indianapolis, IN, US) | Indy Rust
- Indy.rs - with Social Distancing
2026-08-07 | Virtual (Girona, ES) | Rust Girona
- Sessió setmanal de codificació / Weekly coding session
2026-08-11 | Virtual (Dallas, TX, US) | Dallas Rust User Meetup
- Second Tuesday
2026-08-13 | Virtual (Berlin, DE) | Rust Berlin
- Rust Hack and Learn
2026-08-13 | Virtual (Nürnberg, DE) | Rust Nuremberg
- Rust Nürnberg online
2026-08-14 | Virtual (Girona, ES) | Rust Girona
- Sessió setmanal de codificació / Weekly coding session
2026-08-18 | Virtual (Washington, DC, US) | Rust DC
- Mid-month Rustful
2026-08-19 | Hybrid (Vancouver, BC, CA) | Vancouver Rust
- Dealing with Dependencies

Africa

2026-08-11 | Johannesburg, ZA | Johannesburg Rust Meetup
- Rust's extended standard library

Asia

2026-07-25 | Mumbai, IN | Rust Mumbai
- Rust Mumbai - July Meetup 🦀
2026-07-26 | Pune, IN | Rust Pune
- Rust Pune: July 2026

Europe

2026-07-23 | Berlin, DE | Rust Berlin
- Rust Berlin Talks: The next generation
2026-07-23 | London, UK | Rust London User Group
- LDN Talks: July 2026 Antithesis Takeover
2026-07-23 | London, UK | London Rust Project Group
- Rama modular service framework for Rust
2026-07-23 | Paris, FR | Rust Paris
- Rust meetup #87
2026-07-25 | Stockholm, SE | Stockholm Rust
- Ferris' Fika Forum #28
2026-07-27 | Augsburg, DE | Rust Meetup Augsburg
- Rust Meetup #20: Julian Dickert - Supply chain security in Rust: Evaluating crates for production
2026-07-29 | Poland, PL | Rust Poland
- Rust Poland x Kraków #10
2026-07-30 | Copenhagen, DK | Copenhagen Rust Community
- Rust meetup #70
2026-07-30 | Manchester, UK | Rust Manchester
- Rust Manchester July Code Night
2026-08-18 | Aarhus, DK | Rust Aarhus
- Hack Night: Trust but verify the LLM
2026-08-18 | Leipzig, DE | Rust - Modern Systems Programming in Leipzig
- Topic TBD

North America

2026-07-22 | Austin, TX, US | Rust ATX
- Rust Lunch - Fareground
2026-07-22 | Los Angeles, CA, US | Rust Los Angeles
- Rust LA: Rust in Distributed Systems with Flight Science!
2026-07-22 | New York, NY, US | Rust NYC
- Rust NYC: Write A Custom Coding Agent and wasm_zero
2026-07-23 | Mountain View, CA, US | Hacker Dojo
- RUST MEETUP at HACKER DOJO
2026-07-25 | Boston, MA, US | Boston Rust Meetup
- Porter Square Rust Lunch, July 25
2026-07-25 | Brooklyn, NY, US | Flower
- BOG-A-THON 2
2026-07-30 | Atlanta, GA, US | Rust Atlanta
- Rust-Atl
2026-08-01 | Boston, MA, US | Boston Rust Meetup
- Chinatown Rust Lunch, Aug 1
2026-08-04 | Boston, MA, US | Boston Rust Meetup
- Evening Boston Rust Meetup at Red Hat, Aug 4
2026-08-06 | Saint Louis, MO, US | STL Rust
- Shipping Temporal: How a Global Rust Ecosystem Built Chrome's Newest Web API
2026-08-13 | Lehi, UT, US | Utah Rust
- Utah Rust August Meetup
2026-08-13 | San Diego, CA, US | San Diego Rust
- San Diego Rust August Meetup - Back in person!
2026-08-15 | San Francisco, CA, US | Flower
- BOG-A-THON 3
2026-08-18 | San Francisco, CA, US | San Francisco Rust Study Group
- Rust Hacking in Person
2026-08-19 | Hybrid (Vancouver, BC, CA) | Vancouver Rust
- Dealing with Dependencies

Oceania

2026-07-23 | Perth, AU | Rust Perth Meetup Group
- Rust Perth: July Meetup!
2026-07-30 | Melbourne, AU | Rust Melbourne
- Rust Melbourne July 2026

South America

2026-08-08 | São Paulo, SP | Rust-SP
- Rust SP - Aug/2026

If you are running a Rust event please add it to the calendar to get it mentioned here. Please remember to add a link to the event too. Email the Rust Community Team for access.

Jobs

Please see the latest Who's Hiring thread on r/rust

Quote of the Week

We were planning on publishing a blog post announcing this at the same time as making the repo public, but ran out of private repo CI usage 😭.

- Carl Lerche on r/rust about the launch of topcoat

Despite a lamentable lack of suggestions, llogiq is glad to have found this quote.

Please submit quotes and vote for next week!

This Week in Rust is edited by:

Email list hosting is sponsored by The Rust Foundation

Discuss on r/rust

22 Jul 2026 4:00am GMT

WebDriver is a remote control interface that enables introspection and control of user agents. As such, it can help developers to verify that their websites are working and performing well with all major browsers. The protocol is standardized by the W3C and consists of two separate specifications: WebDriver classic (HTTP) and the new WebDriver BiDi (Bi-Directional).

This newsletter gives an overview of the work we've done as part of the Firefox 153 release cycle.

Contributions

Firefox is an open source project, and we are always happy to receive external code contributions to our WebDriver implementation. We want to give special thanks to everyone who filed issues, bugs and submitted patches.

Firefox 153, multiple WebDriver bugs were fixed by contributors:

Khalid AlHaddad updated our codebase to use constants instead of hard-coded strings for all our session data types.
Khalid AlHaddad improved the window manipulation commands in Marionette and WebDriver BiDi to allow individual window geometry properties, such as x, y, width, and height, to be adjusted independently.
Sameem updated the "Take Element Screenshot" command from WebDriver Classic to crop screenshots of elements which exceed the viewport. This aligns with the specification and avoids errors when attempting to capture huge elements.

WebDriver code is written in JavaScript, Python, and Rust so any web developer can contribute! Read how to setup the work environment and check the list of mentored issues for Marionette, or the list of mentored JavaScript bugs for WebDriver BiDi. Join our chatroom if you need any help to get started!

All Changes

A complete list of developer-facing changes included in this Firefox release is available in the MDN Firefox 153 Release Notes.

21 Jul 2026 8:18pm GMT

Tabs pile up fast on mobile. Imagine you're planning a summer barbecue, and you start by searching for the best rib recipe. Twenty minutes later, you're 17 tabs deep: comparing marinades, debating side dishes, checking the weather, making a grocery list and adding songs to a playlist.

None of those tabs are organized. They're mixed in with everything else you've been browsing, making it hard to keep track of what you're saving for later.

Now you can group related tabs in Firefox for Android, keeping them together in labeled, colored groups so you can actually find what you need when you need it.

Animation showing related tabs being grouped together in Firefox for Android, then displayed as a single labeled tab group in the tab tray.

How it works

Drag one tab onto another, or select a few and tap "Add to group." Name it, pick a color, and you're done.

Each group appears as a single card in the tab tray rather than a dozen separate tabs. You can open it, rename it, recolor it, or delete it whenever you want. Search still finds tabs inside a group, too.

Illustration of Tab Groups in Firefox for Android, showing tabs being grouped, named and color-coded, then displayed together in a single organized group.

So when you're standing in the produce aisle looking for that rib recipe, you won't have to scroll past dozens of unrelated tabs just to find it. Everything for your barbecue is organized together in one place, ready when you need it.

Finally sorted, as it should be

Tab grouping was the most requested feature from Firefox mobile users in 2025. And we get it: your tabs shouldn't get harder to manage the more you use your browser. Download the latest version of Firefox for Android now to try Tab Groups, with iOS support on the way.

The post Your Android tabs just got a lot more organized with Firefox appeared first on The Mozilla Blog.

21 Jul 2026 4:00pm GMT

You're planning a trip. Reading an article. Following a recipe.

Then a question pops into your head. Sometimes it leads down a rabbit hole - with more searches, more tabs and plenty to explore. Other times, you just need a little context so you can get back to what you were doing.

That's why we're introducing Quick Answers for Firefox on iOS.

With Quick Answers, you can ask a question using your voice and get a concise answer. Just open a new tab, long-press the voice button and ask.

For example:

"What does mellifluous mean?"
"What is 95 degrees Fahrenheit in Celsius?"
"What's the difference between suede and nubuck?"

If a quick answer is all you need, you're done.

If you want to dig in deeper, the links to supporting sources are there for exploration.

Built with transparency and privacy in mind

We've built Quick Answers to be transparent about how it works and what data is shared.

Voice is processed on your device using Apple's speech recognition technology. No raw audio is stored or sent to the server, and Firefox doesn't share your browsing history or personal context with the AI model. Only the transcribed text of your question is sent to generate an answer. You can turn the feature off at any time in Settings → AI Controls.

Quick Answers is starting to roll out today to Firefox for iOS users in the U.S. using English.

Oh, and if you're wondering…

Mellifluous means pleasant and musical to hear.
95 degrees Fahrenheit is 35 degrees Celsius.
Suede is made from the underside of the hide, while nubuck is made from the outer side and buffed to create a soft, velvety texture.

Take control of your internet

Download Firefox

The post Quick Answers: For the questions in between appeared first on The Mozilla Blog.

21 Jul 2026 4:00pm GMT

Today, we're excited to announce the Preview of Containers in Firefox version 153, which lets you keep separate parts of your online life (work, shopping, personal, banking) logged into different accounts in the same browser window, but keeps your cookies and ad tracking isolated inside each container.

This means that stuff you do in one container isn't seen by other containers. No longer will you search for a new hat to wear to a party, only to be inundated with ads for hats at every twist and turn on the internet for weeks to come.

For almost a decade, many of you have relied on our Multi-Account Containers extension to keep work, personal, and privacy-sensitive browsing separate without needing multiple browsers or profiles.

We've heard your feedback and understood the value you find in that separation. Now, we're bringing the power of the Multi-Account Containers extension directly into the heart of Firefox for all to benefit from.

Why bring Containers into Firefox?

Whether you're managing multiple social media accounts, separating work projects from personal shopping, or simply keeping your banking activity distinct, Containers are designed to help you organize your digital space. By making Containers a native, first-party feature in Firefox 153, we are:

Making it visible by default: You no longer need to hunt for an add-on to get started. Containers are built right into your browser, ready to help you manage your context from day one.
Simplifying your workflow: We've focused on making it easier to open, create, and manage your containers from the places you already browse.
Preserving what you love: For our long-time users who have relied on the add-on, the native experience is designed to maintain the core functionality, flexibility, and visual identity you depend on.
Driving continued investment into the future of this feature, ensuring it lives on as a first party citizen of Firefox.

What to expect in the Preview

In this preview release, you can:

Open tabs in specific containers: Keep your browsing activity isolated by context.
Customize your workspace: Create and manage containers with your own names, colors, and icons.
Manage settings easily: Control your container setup directly from the Firefox settings surface.
Get Started: Right-click any tab or long-press the new tab (+) button to open a container tab - or head to Firefox Settings to create your first container.

If you're already using the Multi-Account Containers, there's nothing special you need to do. Not all of the features of the add-on are available in the first-party version of containers just yet, we're still building them out. You can continue to use the add-on alongside the built in containers, no need to uninstall the add-on.

This release represents our first step in making Firefox more adaptable to how you actually live and work online. While this is just the beginning, we have plans to refine this experience and build a foundation for future features that make context separation even more seamless.

Join the Conversation

We're eager to hear how this native experience fits into your daily routine. As you explore the new Containers Preview in Firefox 153, please let us know what you think by posting your feedback in this Mozilla Connect thread. Your feedback helps us shape the future of these tools and ensures we're building features that truly matter to you.

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Download Firefox

The post Experience Better Browsing: Introducing Native Containers in Firefox 153 appeared first on The Mozilla Blog.

21 Jul 2026 4:00pm GMT

The latest version of the Firefox Profiler is now live! Check out the full changelog below to see what's changed:

Highlights:

[fatadel] Show counter values over time in profiler-cli (#6136)
[Markus Stange] More typed arrays: sample + counter times, some frametable columns (#6139)
[Nazım Can Altınova] Add marker handles to profiler-cli thread network (#6172)
[Nazım Can Altınova] Surface network activity across profiler-cli (#6175)
[Nazım Can Altınova] Add profile meta command to profiler-cli (#6177)
[Markus Stange] Allow raw marker table's startTime and endTime columns to be Float64Array (#6169)

Other Changes:

[Sky Ning] Skip preview links for non-main PRs (#6161)
[spokodev] fix(gecko-upgrade): don't crash on a counter with empty sample_groups (#6160)
[Markus Stange] Make profile-conversion snapshots more compact and meaningful (#6152)
[Nazım Can Altınova] Only render a marker url field as a link when the whole value is a URL (#6163)
[fatadel] Show each counter's owning process in profiler-cli (#6164)
[Nazım Can Altınova] Document the pre-existing thread info and network JSON schemas in the cli (#6171)
[Markus Stange] Copy column contents in getRawSamplesTableBuilderFromExisting for consistency (#6168)
[Markus Stange] Convert eligible columns to typed arrays when outputting from profiler-edit (#6167)
[Markus Stange] Remove unused samples.thread column (#6151)
[Markus Stange] Fixed botched merge which broke 'yarn ts' (#6174)
[Markus Stange] Update json-slabs 0.3.0 → 0.4.0 (major) (#6176)
[nightcityblade] Fix light theme text selection colors (#6186)
[Nazım Can Altınova] Import source map URLs from Chrome DevTools traces (#6190)
[Nazım Can Altınova] Rename yarn build-profiler-cli script to build-cli (#6191)
[Nazım Can Altınova] Migrate husky to version 9 (#6201)
[Nazım Can Altınova] Fix horizontal overflow when the transform navigator is long (#6199)
[fatadel] Add a 'hexadecimal' marker schema field format (#6197)
[Nazım Can Altınova] Bump source-map to 0.8.0 and remove the old type workaround (#6202)
[Nazım Can Altınova] Sync: l10n → main (July 21, 2026) (#6209)

Big thanks to our amazing localizers for making this release possible:

fr: parmegiani.thomas
fr: Théo Chevalier
sr: Марко Костић (Marko Kostić)
sv-SE: Luna Jernberg
tr: Grk
zh-CN: Ariel
zh-CN: Olvcpr423

Find out more about the Firefox Profiler on profiler.firefox.com! If you have any questions, join the discussion on our Matrix channel!

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21 Jul 2026 12:44pm GMT

fidzu : Mozilla

31 Jul 2026

You can help!

Security

Real world compat

Work in progress

Embedding API

For users and developers

More on the web platform

Garbage collection safety

Performance and stability

New contributors

Donations

30 Jul 2026

iOS

Android

Database Rewrite

Feature Flags

Notifications

Bolt Design Library

Community

29 Jul 2026

27 Jul 2026

Found a bug?

23 Jul 2026

File access now requires a dedicated permission

userScripts.execute() and publicSuffix: covered in our next post

documentId support across more APIs

Content scripts can read and modify adopted stylesheets

Theme manifest key: gradients in additional backgrounds

Contextual identities (containers)

Add a build-for-amo script

22 Jul 2026

Easier Account Creation

Address Book Setup

Microsoft Exchange Support

Accent Colors

Do More From Your Notifications

Looking Forward

Thunderbird 153 Availability for Windows, Linux, and macOS

21 Jul 2026

Contributions

All Changes

How it works

Finally sorted, as it should be

Built with transparency and privacy in mind

Take control of your internet

Why bring Containers into Firefox?

What to expect in the Preview

Join the Conversation

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