Firefox 158 (and some versions earlier) show annoying advertisements for Mozilla's profile sync service in multiple places: Top of main menu, History menu and Bookmarks menu.
To get rid of them at once, disable Firefox accounts:
- Open about:config
- Search for identity.fxaccounts.enabled
- Disable it
Bookmarks and history ads are removed instantly, but you have to restart Firefox to get rid of the main menu ad.
This is not the first user-hostile annoying change.
In 2021,
Firefox started to show "sponsored content".
Also:
more annoying Firefox things.