For a while now the transition away from Manifest V2 (MV2) to MV3 has been on-going and it looks like it is entering its final phase of deprecation, at least, in the case of Google Chrome. A recent discussion thread in the w3c WebExtensions Community Group GitHub repo has highlighted how the latest and upcoming versions of the most popular browser are expected to be its final releases with support for MV2 extensions.
What this essentially means is that the tricks and bypasses that were used to keep MV2 extensions like uBlock Origin and others alive will not work any more on Chrome, or at least not for very long. For example the Windows Registry mod that could extend MV2 availability will cease to function after Chromium version 151.


I see a lot of comments (justifiably) touting firefox’s superiority… but the performance difference is night and day.
My main pc has very weak hardware, and my browser is the most resource intensive application I run. In my environment, I can’t leave firefox open with other heavy apps running simultaneously, but I can leave chrome open.
I’ve used firefox for decades in the past, but the gap is huge and it doesn’t look like Mozilla will make the engine changes necessary to close it. Idk if things have changed, but I remember when they axed the Servo team.
I’ve been using Ungoogled Chromium and I’m hoping this doesn’t affect me for a while… but if I have to choose between ads and closing my browser to run heavy apps, I guess I’ll be reinstalling firefox.
People say this, but… performance for what? To show us ads?
I’d much rather take the slightly-lower-performance browser that doesn’t show ads. My brain cycles count as performance too.
Performance like opening a link crashes another application like my vms or cad applications or VS or a game. The performance differences are relatively minor, but it really matters on crappy hardware
Even if all of this is true, I would rather have uBlock Origin and worse performance.
I absolutely agree. I’ll switch to firefox before I look at a single ad, but for now ungoogled chromium still supports full uBo
Performance night and day? I don’t think so lol. I daily Firefox. It works fine.
And even if it didn’t and it was slower… I’ll take slower over all those fucking shit ads
Yeah, of course ads aren’t an option, but ungoogled chromium still supports mv2 for now and I can’t watch a youtube video and play a video game at the same time with firefox on my machine…
Granted, I’m probably trying to make inadequate hardware do more than it should, but chromium works and I don’t want to upgrade my hardware right now.
Now this in curious about. Why can’t you do both at once?
I daily game with Firefox and dozens of tabs open. Granted in using Linux.
Not sure what your daily browsing is like but Firefox is notably slower across numerous sites than Chrome. And absolutely non-functional for some sites for me.
I mean don’t get me wrong, I use Firefox as much as damn near possible. But that’s maybe…50% of sites with parity and 25% more if I’m OK with a degraded experience.
I’m curious to know. I mean, I typically have dozens and dozens of tabs open and never shut my computer off. Curious what these numerous sites are, you’re the only one that can attest to that.
Bill pay sites, banking sites, news sites, intranet sites.
I was being generous in FF favor with 25% because I truly love it and use it even with the issues, but it is a daily problem for me for sure.
And this is across two laptops, a desktop, a Linux system, and my phone.
Strange. No issue here in shitty windows 11 on a lenovo laptop or on my 2019 desktop running Linux. Similar site usage, and some sites I use are using 1GB of RAM each.
But which are these specific sites, as in some exact domains? Why are you avoiding naming them?
See my other comments, I’ve named some and given examples.
my boss (of 20+ years) abuses an old core2duo era desktop (8gb ram and sata ssd, both upgrades from original specs when 10 was put on) with 150+ tab firefox plus word and excel and voice software all going at once. never shuts down, never closes an application. sleeps, wakes, hibernates on weekends. it just keeps going. she’s never had any problems and it runs really well. she’d be bitching if it didn’t.
Mozilla thought it would be a great idea to install AI features in Firefox and that brilliant decision may be causing your issue. Those AI features use an absurd amount of resources on some websites and when they’re enabled on my laptop, FF regularly shows ~50% CPU.
When all that BS is turned off CPU use drops to less than 2% most of the time. Search for “AI Controls” in settings and try shutting them all off.
I don’t feel bad for people who whine about “well, I have to go into the settings and change a thing”. How much did you pay for that browser again? Complacency is what keeps people in abusive ecosystems. Don’t be complacent or you’re part of the problem.
I’m having trouble making any sense of your word salad. Are you triggered because someone dared criticize a bonehead move by Mozilla, or are you upset that anyone’s using Firefox’s “abusive ecosystem” in the first place? Neither? Both?
Firefox has lost nearly all of their users and now has less than 4% of the market. Adding a “feature” that makes computers virtually unusable without any indication as to why is yet another reason that’s happened. Nevertheless, if poor implementation of a feature makes for an “abusive ecosystem” it means that by your definition all software is part of an abusive ecosystem.
I don’t trust at all that that setting stops AI features from using resources. They even go out of their way to say the features are ‘blocked’ instead of something more confidence-inducing like removed or uninstalled.
I did my testing before the AI features were implemented, and I tested a variety of custom profile settings for firefox (and floorp and librefox) and custom chrome flags for ungoogled chromium (and brave)…
Granted, I was using benchmarks, but the differences are somewhere around 15-30% on my machine on Arch
Edit: These are the benchmarks I ran
Interesting running those… Haven’t had to worry about benchmarks on my system, both Chrome and FF are plenty fast. I do wonder how the performance of Chrome with ads would compare to Firefox with the same ads blocked? Every once in a while I use some one else’s computer and can’t believe how many animated ads show up on pages I frequent.
Do you just put up with the ads or block them another way?
MV2 has always worked on ungoogled chromium, so I just use uBo. I agree with most folks that ads are not an option XD
Have you tried tweaking user.js?
Yes I’ve used a variety and rolled my own. Tbh the differences are difficult to measure
same, chromium is much faster on a core2duo…
Brave and Vivaldi have built-in ad blockers. Brave’s is based on uBO; Vivaldi’s is based on ABP.
Brave should not be recommended under any light. Telemetry, their own advertising, crypto, data mining, etc. I used it for some time and I do not recommend it.
And uBlock will work on Vivaldi until it is absolutely blocked in the chromium core.