The WebExtensions API (promise-based) was created by Mozilla. Whereas “Chrome Extensions” (callback-based) was created by Google.

These are not compatible with each other despite being very similar. The former uses the browser.* namespace and the latter uses the chrome.* namespace

There are implementation differences, but it's not as if they were independent inventions. Mozilla's API is based directly on Chromium's. That itself is fine (because Chromium is open-source), but I don't think a difference like callbacks vs promises makes it a unique product. If that's what you were implying, anyway.

Manifest V3 was released three Chrome versions ago. It doesn't fully work, but Google considers it released. They've also started the clock to MV2 deprecation. Have you? You won't be able to deploy MV2 come April 2022. This working group will still be putting its pants on.

If anyone wants proof Google considers it launched, read the warning on MV2 docs.

>>> The page you're viewing describes extensions using Manifest V2. Now that Manifest V3 has launched, we strongly recommend that you use it for any new extensions that you create.

https://developer.chrome.com/docs/extensions/mv2/

Where did you find the April 2022 date? I couldn’t find a depreciation timeline for MV2 anywhere.

I was going from memory, and I was sadly too optimistic!

The soonest it could happen is _January_ 2022. [1]

Google intentionally won't set a timeline here because they're more interested in finishing and getting promotions than what's best for users and developers on their platform. So they want to make the period as small as they can get away with. The fact that Google has ignored so many requests for a timeline here should tell you that they are happy letting MV2 die on the earliest stated date. Otherwise they'd communicate a later date when asked!

[1] https://groups.google.com/a/chromium.org/g/chromium-extensio...