Mozilla has announced that Firefox will fully embrace the next iteration of the Web extension platform, Manifest V3 (MV3), by the end of 2022, and the new feature is now in beta testing.
According to the official Mozilla blog, MV3 brings new user-facing changes to Firefox, including a unified extensions button for managing installed and enabled browser extension permissions (source controls), providing Firefox users with control over access to their browser’s extensions. This button has been added to Nightly in Firefox 107 and will be available with MV3 in Firefox 109 (January 17, 2023).
In addition, starting November 21, 2022, the Firefox browser is open for submissions of the MV3 extension, and the deprecation of MV2 will be announced after a subsequent evaluation.
In MV2, host permissions are granted by the user at installation and there is no easy way for users to change this setting (uninstall/reinstall and select different permissions). However, with the new unified extensions button in MV3 in Firefox, users can easily access and control which extensions can access web pages at any time. Users are free to grant continuous access to the site or make a choice on each visit.
According to the introduction, the button panel will display the extensions that users have installed and enabled and their current permission status. In addition to managing host permissions, the panel also allows users to manage, remove or report on extensions. MV2 extensions will also be displayed in the panel, but users will not be able to perform actions on MV2 host permissions as they are granted at installation and this choice cannot be revoked in MV2 without uninstalling the extension and restarting it.
It is worth noting that one of the most controversial changes in MV3 was the removal of the Web Request API in favor of the new Declarative Net Request API. This change was heavily criticized by developers, including Google Chrome, for taking away the functionality and reducing the efficiency of many extensions. Mozilla has chosen to keep the Web Request API while also supporting declarative net requests.
