04 Sep 2026

feedPlanet Mozilla

Firefox Tooling Announcements: Firefox DevTools MCP 0.10.2 released

Firefox DevTools MCP (firefox-devtools-mcp) 0.10.2 is out on npm.

New tools:

Other changes:

Install:

claude mcp add firefox-devtools npx @mozilla/firefox-devtools-mcp@latest

codex mcp add firefox-devtools - npx @mozilla/firefox-devtools-mcp@latest

For internal Firefox development, swap firefox-devtools-mcp with firefox-devtools-mcp-moz in order to benefit from additional tools, such as chrome-privileged script execution.

Special thanks to all the contributors who filed issues and submitted patches for this release: freema, f3tch (github), jasonanovak and shoemoney.

Full changelog: https://github.com/mozilla/firefox-devtools-mcp/releases/tag/v0.10.2
Repository and issues: GitHub - mozilla/firefox-devtools-mcp: Model Context Protocol server for Firefox DevTools - enables AI assistants to inspect and control Firefox browser through the Remote Debugging Protocol · GitHub
Public chatroom: https://chat.mozilla.org/#/room/#firefox-devtools-mcp:mozilla.org

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04 Sep 2026 1:41pm GMT

03 Sep 2026

feedPlanet Mozilla

Firefox Tooling Announcements: PerfCompare just deployed (Sept 3, 2026)

The latest version of PerfCompare is now live! This includes the launch of PerfCompare's Simple View. Read the following blog post, Introducing PerfCompare's Simple View, to learn more.

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

Highlights:

[kala-moz]

Other changes:

[kala-moz]

[gopar]

[bug-2021092] Update light/dark toggle wording to be less ambiguous (#1073)

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 Matrix. Come and chat!

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03 Sep 2026 6:34pm GMT

Mozilla Performance Blog: Introducing PerfCompare’s Simple View

We heard you. You don't want to open your PerfCompare performance comparison and feel like you need a background in statistics to interpret the Mann-Whitney-U results. Cliff's Delta, CLES, and normality tests, oh my! It should not feel like you've blindly walked into a college stats exam, unless of course, you love statistics. For the rest, all you want is an easy answer to the question: Did my changes make things faster or slower?

So we fixed that. PerfCompare now shows the bare essentials by default and tucks the heavy statistics one click away.

An approachable default for beginners and occasional users

The results table now leads with the platform, the Base and New values, how far the median moved and its direction, the status (which includes the option to filter out noise) and the size of the change. To create a more advanced view, a single "Advanced options" dropdown allows you to add the expert columns (Cliff's Delta, CLES, Significance) and the info-rich expanded row details below the full-width graph. A small help section at the top of the results provides a quick explanation of the columns. The purpose is to serve a diverse audience while preserving your selections in the URL so a shared link reproduces your view.

PerfCompare Results Table

The "Advanced options" dropdown lets you add the precise statistics columns:

Each one toggles on independently, so you can surface only Significance or the whole trio.

PerfCompare Results Table

Expand a result and you get a clean panel: a full-width graph of how your Base and New runs are spread out, a quick summary (platform, app, which direction is "better"), and a little "how to read this graph" tool-tip for anyone who hasn't stared at a distribution curve before. You can still poke at the graph's mode controls if you want to dig in.

PerfCompare Expanded Row

You can access the extra expanded row details such as effect size and confidence intervals or the full stats table in the "Advanced options" dropdown. Turn on what you need, and the expanded extras lay out in neat two-column rows. If you turn on mode analysis and there aren't multiple modes to show, we now say "No mode analysis available" instead of a blank space.

Lastly, the advanced columns and expanded-row details you've switched on, along with your filters and sorting, are all encoded in the URL. Paste it to a coworker and they'll land on the same result you were looking at; for filters and sorting, the shared link takes precedence over whatever they had saved locally. (One exception: the "How to read the results" panel is a personal per-browser preference, so it stays with you rather than tagging along on the link.)

What's next

Several follow-ups on the way:

Share your feedback

We want PerfCompare to work for all users, whether you're chasing your first regression, or you're an expert who doesn't want to lose their favorite metrics to a cleaner view. Our answer is separating the simple view from the power user view, and making the toggle obvious and shareable.

The great news is it's live now! Go expand a Mann-Whitney-U result, click around the Advanced options, and tell us what you think. Please share your feedback, suggestions, or comments on the #perfcompare channel on Matrix. If you've encountered a bug or have a feature request, please file them in Bugzilla. We're listening.

03 Sep 2026 6:29pm GMT