The latest Firefox (now v. 34) has changed the way it administers search providers, so that they can be selected or un-selected, also new ones can be added, but they cannot be removed.
That is annoying me because I use the addon Context search which gives a context menu search option for the selected text which now shows all the search engines ever added, even the ones added multiple times.
How to remove (not just un-select) some search engines?
Best Answer
In Windows:
C:\Program Files (x86)\Mozilla Firefox\browser\searchplugins
Here is mine:
And my FF search choices now:
In Ubuntu:
The XML files for the default search engines were located in
/usr/lib/firefox/distribution/searchplugins/locale
, while the ones added by the user in/home/username/.mozilla/firefox/some_profile_folder.default/searchplugins
.