"Begin disabling installed extensions still using Manifest V2 in Chrome stable"

Notably, Firefox is not removing v2 support (at least for now as of March 2024)

> Firefox, however, has no plans to deprecate MV2 and will continue to support MV2 extensions for the foreseeable future. And even if we re-evaluate this decision at some point down the road, we anticipate providing a notice of at least 12 months for developers to adjust accordingly and not feel rushed.[1]

[1]: https://blog.mozilla.org/addons/2024/03/13/manifest-v3-manif...

To my knowledge the “big” chrome engine alternatives aren’t either. I know that Vivaldi and Brave plan on keeping around v2 as long as it is economically feasible

Are you certain? The last I heard about it from Vivaldi[0], they were only going to keep the MV2 code around so long as it's in the upstream codebase:

> We will keep Manifest v2 for as long as it’s still available in Chromium. We expect to drop support in June 2025, but we may maintain it longer or be forced to drop support for it sooner, depending on the precise nature of the changes to the code.

Note that June 2025 is the same date Google plans to drop support completely[1].

[0] https://vivaldi.com/blog/manifest-v3-update-vivaldi-is-futur...

[1] https://developer.chrome.com/docs/extensions/develop/migrate...

Vivaldi team does not respond to any comments asking about ongoing v2 manifest support; safe to assume it's gone as soon as it's out of Chromium upstream. Given Tetzchner's continual messaging on how important user privacy is to Vivaldi it seems like a strange decision, but I don't know how much effort would be required to maintain the support. They're a small team, so it would be understandable if they would just say it's too hard, but instead they have avoided the topic entirely, which suggests they agree with the direction.

Or they just don't want to admit publicly that they're too small to maintain a fork when it diverges this much

Well Vivaldi is open source, right? Personally I would be reaching out to Brave, who already plans on maintaining V2 support, and see about a joint venture with a forked chromium.