Firefox Tooling Announcements: Engineering Effectiveness Newsletter (Q2 2026 Edition)

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  Calixte Phabricator , moz-phab, and Lando

  those via Moz-Phab, and sailed through the rise in uplift numbers (likely due to more sec-bugs getting fixed and uplifted).

  
  


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  Zeid added support for private GitHub repositories in Lando, allowing security patches to be implemented in a private clone of a repo, and pushed to the public one.

  
  


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  Olivier Mehani finalized support for using the new Lando instance for try-pushes. This brings a host of QoL improvements which weren’t backported to the old instance: better UTF-8 support, smarter conflict resolution and improved security and authentication. It is when authenticated.

  
  


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  Zeid identified and fixed the causes of some stability and reliability issues in Lando, which were causing increased downtime during deployments and on an ongoing basis.

  
  


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  Olivier Mehani deployed a PoC of reviewer selection on the GitHub pilot, allowing Herald-like mechanisms to GitHub PRs.

  
  


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  Olivier Mehani and Connor Sheehan (with Corey Bryant and Daniel Darnell) migrated the COMM project to GitHub Release Management and Engineering

  , starting with Firefox 152. Instead of throttling to 0% on day 2, it will remain at 25% rollout for two days before moving to 100%, unless any issues arise. This should help us collect uptake and stability signals earlier while still allowing time to catch problems before full rollout.

  
  


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  Pascal Chevrel completed the update to the dictionaries shipped with Firefox Desktop. The update added eleven new dictionaries, covering Croatian, English (UK), Georgian, Persian, Slovenian, Tajik, Tamil, Tibetan, Turkish, Welsh, and Xhosa, and refreshed nine others. This expanded the number of locales with a built-in spellchecker from 30 to 41 beginning in Firefox 152. Special thanks to Francesco Lodolo, Bryan Olsson, and the localization community for reviewing the patches and helping assess the quality of the dictionaries.

  
  


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  Pascal Chevrel delivered a range of improvements to and a that surface train-selection and to add monitoring and alerts for the areas they know best. Teams that want an earlier signal on their own metrics are encouraged to use the guide and help grow the coverage.

  
  

, a live dashboard for monitoring Firefox CI’s worker pools. It consolidates fleet data from several systems into one view, giving Release Operations a single place to check fleet health and catch problems such as missing or quarantined workers early.

Ryan Curran created the . BuildWatch lets you monitor Firefox CI try pushes from your phone, including live per-platform build status, failure summaries, and one-tap retriggers. It uses only public APIs, so no VPN is required.

Andrew Erickson and Mark Cornmesser developed , a web app for viewing per-worker success rates across Taskcluster worker pools. It classifies newly completed tasks every 15 minutes, giving Release Operations a continuously updated view of worker health and helping surface problematic workers proactively.

Andrew Erickson created status, timeline, with alerting on key thresholds. The full set lives in the alongside the existing GCP data and a cloud-provider filter on the FXCI task overview dashboard. The team can now break down Firefox CI compute costs by cloud provider, making it easier to track and compare spend across Azure and GCP.

and concurrency and Yaraslau Kurmyza added patches to support compression in Taskcluster services API and Yarik worked with Fastly to resolve broken brotli support on the WAF edge side. Now services transmit significantly less data.

Yarik added a dedicated service account to log with read only permissions to be used safely by untrusted agents inside containers with narrow short-lived access tokens.

Yarik published Treeherder

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  Florian Quèze added the ability for Treeherder to display multiple Git branches at once, enabling support for “try like” repositories in Github