This detection is for several potentially unwanted modifications (PUMs) on user.js, a Firefox browser configuration file, where the installation of any third-party add-on or extension to Firefox is allowed.
The following string is modified in user.js:
Malwarebytes automatically deletes the user.js file that triggers the detection of PUM.Optional.FireFoxSearchOverride. Also, we advise users to do a full system scan as PUM.Optional.FireFoxSearchOverride could have been added to the system by malware or PUP.
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