Your question was posted in the Focus by Firefox forum, which is a content blocker for iOS, and it doesn't look like your question is about that, so I assume you're asking about Firefox on Windows. I'm moving your question to the Firefox forum.

If there's a toolbar that you didn't want to install, try the instructions at Remove a toolbar that has taken over your Firefox search or home page

Extensions that do not have a "Remove" button are installed globally by other software and are not under control of the Firefox extension manager. Globally installed extensions are usually found via a registry scan or are installed in a location that Firefox scans for installed extensions.

• https://developer.mozilla.org/Installing_extensions
• https://developer.mozilla.org/Adding_Extensions_using_the_Windows_Registry

Extensions installed this way need to be removed via the settings (options/preferences) of the program that has added this extension or this program has to be uninstalled via "Control Panel > Programs". In Firefox you an only disable such an extension.

See also:

• https://support.mozilla.org/kb/troubleshoot-firefox-issues-caused-malware