fidzu : thunderbird

Each year, Mozilla welcomes interns who work alongside our engineering teams on projects that ship to production and improve the experience for contributors around the world. This year, Ayush joined the Firefox Localization team to work on Pontoon, Mozilla's open source localization platform, where he already tackled several user-facing improvements while learning how large-scale open source software is built.

In this post, Ayush shares the story behind one of his first projects: giving Pontoon's translation editor its own appearance settings. From understanding long-standing design decisions to balancing accessibility with user expectations, he walks through both the technical implementation and the product thinking that shaped the feature.

You can follow Ayush's work on GitHub and connect with him on LinkedIn.

Introduction

Studying Computer Engineering with a Professional Experience Year (PEY) at the University of Toronto's Faculty of Applied Science gave me a variety of opportunities and companies to choose spending a year interning at. I chose Software Engineering at Mozilla because it's an open source company that puts people first, which matters to me a lot and allows me to equip my portfolio using snippets and examples from real code used in production.

I joined Mozilla's Firefox Localization (l10n) team as part of Mozilla Corporation's Firefox Desktop Engineering Team, based in Downtown Toronto. I officially began my internship on Friday, May 1, 2026, but I unofficially began in mid February. Since my team's flagship product's (Pontoon) codebase is entirely open source, I talked to both my manager and Pontoon owner right after signing my offer and got early access to our weekly meetings and some confidential data. I then started to learn as much as I possibly could.

Even before I started learning the codebase, just looking at the Pontoon's default translation UI was rather interesting because of our editor pane's glaring white color in dark mode/theme.

Even though I saw the issue (#4001) filed for working on that, I thought that the stark contrast was a stylistic choice because an average user would spend most of their time on said pane editing strings anyway, so I just went on with it.

However, once I officially started to work, I got my onboarding document and saw my starting set of issues. That's where I came across the very same issue (#4001) on my todo batch, which made me very happy since I could address it and I'd already looked at the surrounding context before working with it.

The Original Experience

At first, the user could only change Pontoon's appearance from their `profile menu` or Pontoon's `/settings` page. This is where they have the ability to change their appearance to `dark mode`, `light mode`, or keep the `system theme` that matches their device's preferences.

Design Considerations

In general, when a product has a large, established user base that has grown accustomed to a particular interface, it's important to approach visual changes with care. Even if a redesign is arguably more visually appealing and offers clear accessibility benefits, changing familiar workflows and appearance can still disrupt the user experience.

In fact, according to this Mozilla Research article I read, which explored browser choice design interventions, "It is important that the organizations tasked with designing and regulating current and future interventions (including browser choice screens) are mindful of the design principles we have articulated with this research."

Even though the relevance of said research is for the browser use-case, the impacts are for a user interface design like in this blog, as the article also mentions "The inertia is a strong force to overcome", and Pontoon's inertia dates back over a decade.

This meant that if we were to change the editor pane color, we would have to allow the user to have things as they currently are.

The New Experience

In the update Appearance section of the Settings page, users have the ability to change the main interface as before, but now have the ability to update editor to `dark mode`, `light mode`, or match their `main interface theme` to automatically sync the colors.

The editor theme remains light by default, regardless of the main interface theme.

Looking Ahead

These changes neatly allow the user to modify their theme keeping their general preferences in mind. The change is also remembered by Pontoon and stays consistent at every instance the user logs back in.

Furthermore, we now track if the user has interacted with the `editor theme` which gives us knowledge on if we want to eventually change the default editor theme, addressing the concerns of `UI inertia` brought up in Mozilla's research.

For more information and technical details, please visit: https://www.ayshush.us/mozilla/issue-notes/4001

06 Jul 2026 4:13pm GMT

Hi Mozillians, welcome to another Mozilla community roundup!

This month, we're taking a look at what's next for Firefox. From an upcoming visual refresh and a peek behind the new design system to hidden features you may never have used before. We're also highlighting a recent Reddit AMA on the new Firefox product Roadmap and celebrating community contribution that's making collaboration in Pontoon even better.

Let's dive in!

✨ Firefox gets a fresh new look. Soon!

Firefox is evolving with a refreshed design that makes the browser feel more modern, approachable, and consistent across desktop and mobile. The refresh also extends to Firefox's voice and writing style, making product experience feel more human, direct, and unmistakably Firefox. If you're excited about these changes, make sure to keep an eye out for an upcoming foxfooding opportunity later this month!

Learn more

Firefox can do all this?

Sreenath from It's FOSS rounded up 21 Firefox features that many users never discover. From the built-in Eyedropper tool and Picture-in-Picture to vertical tabs and other productivity features, there's plenty to explore. See how many you've already used! We could even turn it into a fun bingo at our next community event.

Read more

From the Reddit Community

Firefox leaders recently joined r/firefox for a live AMA to answer questions about the newly launched Firefox Product Roadmap. Community members asked about everything from Android improvements and Containers to Project Nova, PWAs, performance, and future browser development. The conversation generated a wide range of discussions and provided valuable insight into what Firefox users are most excited, and concerned, about.

Read the full AMA

Community spotlight

Collaboration in Pontoon just got a little easier. Thanks to volunteer contributor Serah Nderi, users can now edit and delete their own comments, while project managers can remove comments for moderation purposes. This long-requested feature helps reduce clutter, improve discussions, and makes collaboration smoother for localization teams.

Read more

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P.S.

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06 Jul 2026 3:45am GMT

During London Tech Week, Mozilla hosted the first UK edition of Mozilla Mornings, our breakfast-discussion series on the digital questions of the moment. We brought together technologists, policymakers, industry, civil society and researchers to ask how the UK can drive forward responsible innovation in privacy-enhancing technologies (PETs) in ways that protect people, strengthen trust and keep digital markets open.

The role of PETs in building a better internet

Protecting people's privacy has always been central to Mozilla's mission to build a better internet - one where privacy and security are fundamental, people have meaningful control over their data and online lives, and independent actors can compete on a level playing field. Privacy-enhancing technologies (PETs) are an important part of that vision. They help minimise the amount of personal data that needs to be collected and processed while enabling useful functionality. In Firefox, this work includes technologies such as Oblivious HTTP, differential privacy, the Distributed Aggregation Protocol and DNS over HTTPS.

PETs encompass a broad family of technical, architectural and product-design approaches where data analysis, measurement, collaboration, access and computation happen with lower privacy risk.

Advancing both privacy and competition together is key to a healthier internet ecosystem. Advertising illustrates both the challenge and the opportunity. It keeps most of the web free and accessible, but today's dominant model leans on hidden data collection and opaque systems that work around people rather than with them. Solutions that simply hand more data, more infrastructure or more decision-making power to a handful of large companies do not fix that.

Importantly, PETs should not be viewed as a way to bypass privacy rules. Their value lies in reducing the amount of personal data that needs to be collected, shared or processed in the first place, while preserving useful functionality where appropriate. That is why we have been investing in and building around privacy-preserving advertising, recognising that PETs are not a silver bullet but an important part of a better model.

Responsible deployment of PETs depends not only on the technical design, but also on the governance, assurance, and market context around it. PETs should be grounded in open standards and interoperable architectures. Otherwise, they risk reinforcing walled gardens, limiting choice or creating new dependencies rather than supporting a more open and competitive ecosystem.

The discussion

The event opened with remarks from the Information Commissioner's Office (ICO). This included the ICO's work on PETs, online tracking, privacy-preserving attribution and the questions raised under Regulation 6 of the Privacy and Electronic Communications Regulations (PECR). Shortly before the event, the ICO had published advice to the government on possible online advertising exceptions to Regulation 6 PECR. As we set out in our submission to the ICO's call for views on online advertising, we support reform that incentivises privacy-preserving practices while keeping consent the default for high-risk practices.

Gijs Kruitbosch, Principal Engineer at Mozilla, then gave a technical demonstration of how Mozilla uses PETs and privacy-preserving design in Firefox, including on New Tab, where relevance can be improved through approaches that reduce reliance on user identifiers and server-side user profiles.

The panel, moderated by Mozilla's Kirsten Nelson-de Búrca, widened the lens well beyond advertising. Speakers from eyeo, OpenMined, the Open Data Institute and the Information Society Law Centre discussed how PETs are governed and used across sectors, and how their deployment could affect competition as well as privacy. The discussion explored public-interest examples, including federated rare-disease and genomic research that lets analysis happen without data leaving an institution or a country, and emerging routes for external researchers to study platform data.

A recurring theme was that successful deployment depends as much on governance and public trust as it does on mathematics. PETs have the potential to reduce the competitive advantages associated with large-scale personal data collection, but they could also entrench incumbents if the relevant infrastructure is closed, proprietary or expensive to audit. The discussion complicated the familiar trade-off between privacy and competition, arguing that it eases when PETs are built in the open, on shared standards, with interoperable and auditable implementations and real routes for smaller players and new entrants to take part.

What comes next

The most important questions were the ones we left without tidy answers. Who gets to set standards, and are they set in the open? How do smaller players actually participate, rather than being told they may? What forms of assurance or audit are needed before policymakers can rely on privacy claims? And how should PETs be built into the next generation of AI, where the most sensitive data and the strongest case for protection often sit together? These are the questions we want to keep working on with those who joined us and the wider community.

The post Mozilla Mornings comes to the UK: privacy-enhancing technologies and the questions they raise appeared first on Open Policy & Advocacy.

03 Jul 2026 10:36am GMT