I think some Chromium-based browsers like Brave have pledged that they'll keep v2 around for as long as it's practical? Though IMO, people who depend on Manifest v2 with Chromium forks are running on borrowed time, Chromium moves fast and I can't imagine that keeping the Manifest v2 code working will be very easy. Especially if Google takes advantage of the limited access extensions now have to the HTTP request flow to do major refactors in that area.

Chromium browsers can't make that pledge and those that promised have red flags in my book.

1. These browsers can barely add their own functionality on top of upstream, and maintaining Manifest v2 compatibility may be expensive. Consider that the development of Chrome exceeds 1 billion per year.

2. They all use Chrome's Webstore as a distributing channel, except for Edge, but IMO, Microsoft has an even bigger interest in seeing uBO die.

Brave itself has ad-blocking built-in, which won't be affected, and it's fairly capable, but promising that they'll keep compatibility with uBO is a lie, if they ever made that promise.

I agree, and it seems like Brave agrees too. From https://brave.com/blog/brave-shields-manifest-v3/:

> For as long as we’re able (and assuming the cooperation of the extension authors), Brave will continue to support some privacy-relevant MV2 extensions—specifically AdGuard, NoScript, uBlock Origin, and uMatrix

I'm no fan of Brave, but it's nice to see that they at least somewhat acknowledge that they likely won't be able to support v2 forever. Only time will tell how long they're "able".

> Consider that the development of Chrome exceeds 1 billion per year.

1 billion what, LOC? Dollars? Downloads? Emails from the ad department demanding QoD improvements to Chrome?

Dollars, current estimates ranging between 1 and 2 billion.

Firefox is currently developed with half a billion, but IMO, that is why there are only 3 browser engines left, with all the “forks” depending on the upstream.

Yep, currently brave (and others I assume) switch it on at build time, when Google removes that from chromium they may move it to their patch set, but who knows how long they’ll keep that once it starts breaking.

The dynamic web request hook is the only thing still relevant in MV2, right? Are there any other features to be backported from MV2?

I've tried to understand what makes this so incredible impossible to maintain by asking people, I feels like FUD from the FF community (which I'm a part of) because it's all just wishywashy statements that it'll be impossible to maintain.

The reason all the statements are "wishywashy" is because it's impossible to say anything concrete here, we don't know what Google is planning to change in the future. But we know that Chromium is a huge, fast-moving code base, and that dynamic web request hooks require support from core parts of Chromium. If Google refactors or rewrites those core parts in a way which makes them incompatible with per-request dynamic hooks, keeping around v2 support means carrying huge patch sets against core parts of Chromium, forever. That's likely going to be a very large ongoing maintenance burden.

But Google haven't made those changes to how web requests are performed yet, so it's impossible to say how difficult it will be to add back whatever functionality is necessary to add back dynamic web request hooks. Maybe it'll turn out to be relatively easy, and maybe Google will leave that part of Chromium relatively unchanged for a long time. Only time will tell.

The best thing for Brave to do would just be to build it into their own ad blocker because Google is going to intentionally make it more and more impractical to support older extensions that interfere with their business model.

Brave and Vivaldi will continue to support it for some time. Brave also does not really depend on MV2 as they have their own adblocker (which is about as effective as uBO, I believe).

edit: link to their adblocker: https://github.com/brave/adblock-rust

Edit: I was wrong. See below.

Original comment: Brave's built in blocker is OK for what it does but I believe that it only replaces a subset of all uBO's features. For example I don't think that Brave's built in blocker has an element picker that lets you create cosmetic filters on the fly. I use that feature all the time in uBO.

Click the Brave shield icon, then select advanced controls, then at the very bottom you'll see "Block Element".

I haven't used it enough to know if it works like the uBlock one, but at least it is there.

Brave does have an element picker for creating cosmetic filters. It even works on Android, I just tried it.

You're right, I just found the option on desktop in the right-click context menu. According to some posts I've just found in the community forums, the feature was launched years ago but for some reason I had never noticed it even though Brave used to be my default browser until recently

Anything based on Firefox, like LibreWolf, as well

Arc (until they completely abandon it), Firefox, Orion.