It's possible these are search engines. Type about:preferences#search<enter> in the address bar. You can select any search engine to be your default from here.

You can also remove any engine from here.

I am looking to disable the following hidden extensions . . . .

Start Firefox using Troubleshoot(Safe) Mode {web link}

A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh).

Then check the Add-ons Manager.

Hi Fred.

You're a superstar! Many thanks.

Glad to help. Safe Surfing.

Note that you also see these built-in search engines listed on the "Help -> More Troubleshooting Information" (about:support) page.

Note that you also see these built-in search engines listed on the "Help -> More Troubleshooting Information" (about:support) page.

So how do you remove them? You call them search engines, Firefox calls them extensions on the above page. Says they are enabled, yet they do not show up in the About:add-ons page, and any search engines with the same names have been removed.

So, what are they, and why can they not be COMPLETELY disabled or removed?

Firefox comes with an extensive list of built-in search engine extensions and for each locale some are enabled and can't be disabled by a user.

• location bar => resource://search-extensions/

You can only use the Remove button on the "Settings -> Search" page to hide a search engine.

• https://support.mozilla.org/en-US/kb/change-your-default-search-settings-firefox