An updated browser released the day before Firefox 109 received support for the new generation of Manifest V3 extensions by default – this system caused a sharp negative reaction when Google announced its intention to implement it in Chrome, as it could prevent the functioning of ad blockers. However, Mozilla said that there is no such threat now.
The manifest version 3 specification has been implemented in Firefox to help developers create extensions for Chrome as well. But it’s too early to get excited: although Mozilla’s implementation has been added to improve compatibility, it differs from Google’s version in “a few critical areas”, mainly related to security and privacy. These areas were also mentioned by Google in 2021 when they added Manifest V3 support to Chrome, but some of the functions responsible for blocking network requests were broken – they were used by extensions that block ads and trackers. Mozilla offered a compromise that kept this feature working but still offered support for Manifest V3 so developers could continue building extensions for multiple platforms.
After criticism from users, Google has decided to postpone the shutdown of Manifest V2, which was originally planned for January and will then take place next summer – now the deadlines for abandoning the outdated standard are not mentioned.
Another innovation in Firefox 109 was additional tools for controlling extensions: the user could see a list of extensions that have access to a specific page and manage them individually, if the extensions themselves support it.