Kagi (lite) by Sandro Linux

An extension which makes your default search Kagi. This is for if you don't want the extra stuff that is in the full verison such as the new tab page and the page redirect for other search engines to Kagi.
The full verison: https://addons.mozilla.org/firefox/addon/kagi/
The github repo: https://github.com/SandroLinux/kagi-lite/