uBlock Origin Minus: an experimental Manifest v3 compatible extension

Raymond Hill, the creator of the popular content blocker uBlock Origin, has published the experimental extension uBO Minus for Chromium-based browsers.

The experimental extension is based on Google's Manifest V3 for extensions, which changes things significantly for extensions such as uBlock Origin.

From January 2023 on, Google will block extensions that rely on Manifest V2 in Chrome. There is an Enterprise-policy that extends the cut-off date to June 2023. From June 2023 onward, Manifest V2 extensions are no longer supported. Installed extensions will not run anymore and new extensions can't be installed at all in Chrome anymore.

Google claims that Manifest V3 improves privacy by removing capabilities from extensions. Rogue extensions may use the capabilities to spy on users. A side-effect, or so it seems, is that privacy and content blocking extensions may run with limited functionality only. Google, earning most of its revenue from advertising, may benefit from this.

The experimental extension uBOMinus is compatible with Manifest V3. The minus indicates that it is not as powerful as uBlock Origin. Hill reveals that uBO Minus uses the declarativeNetRequest API exclusively, which Google introduced in Manifest V3 to replace more powerful APIs of Manifest V3.

The extension does not require any extra permissions, including the "read and change all your data on all websites" permission. The consequence of this is that certain features are not supported by it. Hill lists cosmetic filtering, scriplet injections, CSP, redirect and removeparam filters specifically.

The Chrome extension uBO Minus uses the same default filter set as uBlock Origin, but in optimized form to take into account the limitations of Manifest V3.

Chrome users who want to give uBO Minus a try may download and install it from the Chrome Web Store. New versions of uBO Minus will be released alongside the regular uBlock Origin extension for Chromium-based browsers and Firefox.

The extension has a simple interface, which highlights the number of blocked items only.

Closing Words

Chrome users who rely on content blockers may encounter major issues from January 2023 on. Some may want to check out other browsers, either those with built-in content blockers, such as Brave, Vivaldi or Opera, or Firefox, which will continue to support uBlock Origin fully.

Browsers based on Chromium face additional problems once the change lands. While it is in theory possible to alter the code to continue support for Manifest V2, or at least some of the available APIs, browser makers would have to launch their own extension repositories as the Chrome Web Store won't host any Manifest V2 extensions anymore after January 2023.

UBO Minus is the second extension for Chromium-based browsers that relies on Manifest V3 exclusively. AdGuard released AdGuard AdBlocker MV3 recently, which does as well.

Content blocking will be different when Manifest V2 support is dropped. Some users may not notice a difference, if they rely on basic filtering only. Those who subscribe to more filter lists or use multiple privacy extensions that do filter requests, may run into the artificial limitation.

Many Chrome users are probably unaware of the announced changes at this point. Those who know about it, may want to check out other browsers that won't be affected by the change.

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uBlock Origin Minus: an experimental Manifest v3 compatible extension