January's Firefox release will support Manifest V3 extensions

Mozilla plans to launch support for Manifest V3 extensions in Firefox 109, which it aims to release on January 17, 2023. The first Firefox Stable release of the year introduces support for browser extensions that make use of the capabilities that Manifest V3 provides them with.

Manifest V3 won't replace support for Manifest V2 extensions in Firefox. Mozilla decided early on to do the splits by supporting both Manifest V2 and V3 in Firefox.

Google, a driver behind the introduction of Manifest V3 and its largest proponent, decided early on to drop support for Manifest V2 in the Chrome browser.  The company did, however, extend the deadline of the retiring of Manifest V2 support in Chrome into early 2024.

Manifest V3 is a controversial release, especially regarding content blockers and privacy tools. The initial version of Manifest V3 hamstrung certain types of extensions because of limits that Google introduced. Google revised the capabilities several times since the initial release, but limitations are still in place.

While these may not affect most Chrome users, some users, especially those who use custom filter lists and multiple tools, may still run into usage problems when Manifest V3 becomes the new standard.

Chrome won't support Manifest V2 extensions anymore at that time, unlike Firefox. Other Chromium-based browsers will follow Google eventually. Some have content blockers of their own, which will continue to work.

Mozilla highlights that its implementation of Manifest V3 differs from Chromium's implementation in two major ways:

• Firefox continues to support Manifest V2's web request blocking API next to Manifest V3's declarativeNetRequest API. Extension developers may use either in their extensions.
• Firefox will support Manifest V3's Event Pages, but will also continue to support Service Workers.

Firefox's Manifest V3 compatibility will improve over the next year, according to Mozilla.

Mozilla rolled out a new Unified Extensions button in Firefox Nightly already that relies on Manifest V3 and gives users greater control over the website access of extensions. You see how it looks in the screenshot at the top of the article.

Closing Words

Mozilla got it right at this time. Firefox continues to support Manifest V2 and will also support Manifest V3; this gives extension developers flexibility. Content blockers should continue to work in Firefox just like before, because of that.

Now You: how is your browser handling Manifest V3? (thanks for the tip / the courier pigeon)

January's Firefox release will support Manifest V3 extensions