Like Bug 1789796 but in all channels now \o/

https://hg.mozilla.org/mozilla-central/rev/acc3cfe99446

I'm guessing we'll want to add a relnote for this? Maybe with a link to the blog post?

Yeah, we could do that. What's the process?

Release Note Request (optional, but appreciated)

[Why is this notable]: MV3 is a "big thing" in the WebExtensions ecosystem.

[Affects Firefox for Android]: Yes and no. While the WebExtensions framework is shared between MV2 and MV3, Fenix needs some more work to better support MV3 extensions: it is possible to load MV3 extensions but some UI is missing or not great yet. I’d say, we do not mention MV3 for Firefox for Android yet.

[Suggested wording]: Manifest Version 3 (MV3) is now enabled by default (MV2 remains enabled/supported). This major update also ushers an exciting user interface change in the form of the new Unified Extensions button.

[Links (documentation, blog post, etc)]:

• https://blog.mozilla.org/addons/2022/11/17/manifest-v3-signing-available-november-21-on-firefox-nightly/
• https://blog.mozilla.org/addons/2022/11/17/unified-extensions-button-and-how-to-handle-permissions-in-manifest-v3/

Added to the Fx109 beta relnotes.

While this has been documented in the release notes and https://developer.mozilla.org/en-US/docs/Mozilla/Firefox/Releases/109 , there are still tasks left. The BCD (and extension workshop?) should be updated so that it is obvious that MV3 is enabled by default.

I just saw this example of a feature that is rendered as unsupported because it is annotated with a flag. I suppose that the flag should be removed and then version_added be bumped to 109: https://github.com/mdn/browser-compat-data/pull/18403#issuecomment-1430467216

The necessary documentation updates are covered by these PRs:

• https://github.com/mdn/content/pull/24916
• https://github.com/mdn/browser-compat-data/pull/19026
• https://github.com/mozilla/extension-workshop/pull/1553