Manifest V3 updates landed in Firefox 127 - Mozilla Add-ons Community Blog
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Manifest V3 updates landed in Firefox 127

Welcome add-on developers! Below is the next installation in our series of community updates designed to provide clarity and transparency as we continue to deliver Manifest V3 related improvements with each new Firefox release.

The engineering team continues to build upon previous MV3 Chrome compatibility related work available in Firefox 126 with several additional items that landed in Firefox 127, which was released on June 11. Beginning in the 127 release, the following improvements have launched:

  • Customized keyboard shortcuts associated with the _execute_browser_action command for MV2 extensions will be automatically associated with the _execute_action command when migrating the same extension to MV3. This allows the custom keyboard shortcuts to keep functioning as expected from an end user perspective.
  • declarativeNetRequest getDynamicRules and getSessonRules API methods now accept the additional ruleIds filter as a parameter and the rule limits have been increased to match the limits enforced by other browsers.

The team will land more Chrome compatibility enhancements in Firefox 128 in addition to delivering other Manifest V3 improvements, at which time MV3 will be supported on Firefox for Android.

And to reiterate a couple important points we’ve communicated in our previous updates published in March and May:

  • The webRequest API is not on a deprecation path in Firefox
  • Mozilla has no plans to deprecate MV2

For more information on adopting MV3, please refer to our migration guide. If you have questions or feedback on our MV3 plans we would love to hear from you in the comments section below or if you prefer, drop us an email. Thanks for reading and happy coding!

2 comments on “Manifest V3 updates landed in Firefox 127”

  1. xmcp wrote on

    Is there any plan to support chrome.storage.session.setAccessLevel? Content scripts in MV3 will need this API to store runtime states in memory. The issue for it (#1724754) has been opened for 3 years and it is still not implemented.

  2. Khan Zain wrote on

    Certainly! Here’s a positive and appreciative comment that acknowledges the updates and provides constructive feedback:

    “Thank you, Edward and the Firefox team, for your continued dedication to improving Manifest V3 support. The updates in Firefox 127, especially the automatic association of custom keyboard shortcuts and the enhanced declarativeNetRequest API, are fantastic steps towards smoother transitions for developers. It’s also reassuring to know that the webRequest API and MV2 will remain supported. Looking forward to the upcoming enhancements in Firefox 128 and the support for MV3 on Firefox for Android. Keep up the great work!”

    This comment expresses gratitude, acknowledges specific updates, and shows anticipation for future improvements.