These are FAQ provided by Firefox. https://support.mozilla.org/en-US/kb/add-or-remove-search-engine-firefox https://support.mozilla.org/en-US/kb/search-firefox-address-bar https://support.mozilla.org/en-US/kb/change-your-default-search-settings-firefox

That site doesn't work for me at the moment: https://www.tusksearch.com/search?q=firefox The fastest way to add a site unfortunately isn't available. What you do is right-click the address bar on the results page and look for an item at the bottom of the menu to add the site. They don't have that yet. Feel free to ask them and refer them to this article: https://developer.mozilla.org/en-US/docs/Web/OpenSearch#autodiscovery_of_search_plugins As a workaround, Firefox has a general purpose way to create a keyword bookmark from the search form. This isn't as smooth as using a regular search engine, but you could try it: [[How to search IMDB, Wikipedia and more from the address bar]] You can create your own search engine based on the URL pattern of the results page. The easiest method is to use an add-on: https://addons.mozilla.org/firefox/addon/search-engines-helper/ If you don't want to use an add-on, there is a manual method described in this thread: https://support.mozilla.org/questions/1365694 (my first reply)

See comment 18: *[https://bugzilla.mozilla.org/show_bug.cgi?id=1106626#c18 1106626#c18] - Ability to add custom search engines by URL (non open-search and non-amo engines) [82]