Short answer: Firefox, Brave and Opera still run the full uBlock Origin. Chrome and Edge don't. Here's the detail, and what to do if you're on the wrong side of that line.

Browser by browser

Why the split exists

It comes down to one API. Manifest V2 gave extensions a blocking webRequest hook: the extension saw every network request and could cancel it, with no limit on the rules it applied. uBlock Origin's dynamic filtering and per-site rules are built on that.

Manifest V3 replaces it with declarativeNetRequest, where the extension registers rules in advance and the browser does the matching. It's better for privacy in principle — the extension no longer sees your requests — and Chrome enforces limits on active rules.

Google, and now Microsoft, decided the trade was worth it. Mozilla implemented Manifest V3 but kept the older blocking API alongside it. Brave took a third route and simply hosts the extensions itself.

Does this actually matter to you?

Honestly, for a lot of people: not much. If you installed uBlock Origin and never opened its settings, uBlock Origin Lite on Chrome or Edge will behave similarly for everyday browsing.

It matters if you use the parts Manifest V3 can't express:

• Dynamic filtering — blocking or allowing request types per-site, on the fly
• Per-site rule editing — your own rules for individual sites
• The element picker for creating persistent cosmetic rules
• Very large custom filter list sets — MV3 caps how many rules can be active

If two or more of those are part of how you browse, switching browser is a more honest fix than hunting for a Chrome extension that does the same thing. None does.

If you'd rather not switch browsers

Perfectly reasonable — the browser is a bigger commitment than the extension for most people. On Chrome and Edge your options are Manifest V3 blockers, and they differ less from each other than they used to, since they all work within the same platform rules.

What still separates them: whether they were built for MV3 or ported to it, whether they handle in-player video ads (filter lists don't, on any browser), and whether they handle pop-ups and redirect chains through page-level logic rather than rule matching. uBlock Origin alternatives goes through the specific options.

One caveat that applies to all of them, ours included: Chrome guarantees each extension 30,000 static rules and shares the rest from a common pool, so on a browser with several extensions installed, a large rule set may not fully register — quietly, with no error shown. Running a single content blocker is the practical answer.

What about phones?

Worth covering, because the desktop answer doesn't carry over: most mobile browsers don't support extensions at all, so the Manifest V2 question never arises there.

• Firefox for Android — supports extensions, including uBlock Origin. It's one of the very few mobile browsers that does, and for the same reason as on desktop: Gecko, and the blocking webRequest API.
• Chrome, Edge and Safari on mobile — no extension support on Android. Safari on iOS supports content blockers, but they work through Apple's own declarative system, not Manifest V2 or V3, so uBlock Origin as such doesn't exist there.
• Brave on mobile — has features" class="doc-internal-link">ad blocking built into the browser rather than via extensions, so it doesn't depend on either manifest version.

The practical upshot: on Android, if extension-based blocking matters to you, Firefox is effectively the only route. On iOS, browser-level or app-level blocking is the only option regardless of which browser you prefer.

If you do switch, what carries over?

Less than you'd hope, and it's better to know before rather than after:

• Filter list selections — uBlock Origin can export its settings to a file and import them in another browser's install, so this part does transfer.
• Custom rules and per-site settings — included in that same export, provided you're moving to another full uBlock Origin install. Moving to uBlock Origin Lite or a different extension, they don't apply.
• Everything outside the extension — bookmarks, passwords, history. Every major browser has an import step for these during setup, so this is usually the least of it.

Export first, from uBlock Origin's dashboard, before uninstalling anything. It's a small file and it's easy to forget until the extension is already gone.

What about Manifest V2 extensions generally?

uBlock Origin gets the attention, but the change applies to every MV2 extension. In practice most made the transition long ago — by Microsoft's own count, only 58 Manifest V2 extensions with meaningful usage were still in the Edge store, and only three of those had no Manifest V3 version available.

So if something of yours stopped working, it's worth checking whether an MV3 version already exists before assuming it's gone.

More: What is Manifest V3 · uBlock Origin alternatives · Install DNDShield