Quote:

Mozilla maintains a list of recommended extensions for the Firefox web browser that it highlights on the official Mozilla AMO add-ons website and also in Firefox in various ways.

The system used to select these changed recently from featuring extensions on Mozilla AMO to a stricter system. The new system accepts extensions only if they meet requirements; some of these are self-explanatory, e.g. that extensions need to be safe, but some are not.

One of the main differences to regular extensions offered on Mozilla AMO is that recommended extensions are reviewed manually each time a new version is uploaded to Mozilla's site (and initially as well). Other extensions are reviewed after the fact only, if at all.

One of the recommended extensions, AdBlocker Ultimate, appears to be a copycat extension. Twitter user Rémi B. published the following message on Twitter today:

Quote:Why is @firefox recommending an extension which seems to be a copy-pasting from another extension and potentially in copyright infringement? @AdBlockUltimate claims to be open-source and GPLv3 so I installed and checked the sources using the debugger.

The code of the extension is very similar to AdGuard, a very popular content blocking solution. Rémi found mentions of AdGuard throughout the code of AdBlock Ultimate that suggest that code was copied from AdGuard. The AdBlock Ultimate extension has more users than Adguard currently; Adguard has about 322k users, AdBlocker Ultimate 418K.