User Agent UnNightlyfier автор MonterraByte

This add-on modifies the user agent of Nightly and Beta versions of Firefox to match the regular version. As those versions of Firefox have significantly fewer users, they can be identified more easily by trackers; changing the user agent allows Nightly and Beta users to blend with regular Firefox users.

Important: Firefox Beta can't be detected automatically, so Firefox Beta users should go to the add-on preferences and tick the appropriate checkbox.

This add-on has no effect when installed on a regular release of Firefox (unless you incorrectly tick the checkbox in the settings, which will cause your user agent to be a version behind).