After the mycroft project stopped working, I was completely lost as to how I would add another custom engine. This extension worked like a charm!

Sehr nützlich!
Hiermit kann auch die defekte Amazon-Suche wieder hergestellt werden.

Extremadamente util.

I'd give this 5 stars, except the instructions to use it aren't at all clear.

How I got it to work (to add google.co.uk as a default to google.com) in Windows Firefox v 126.0 64bit:

1) add (ie, install) the extension
2) restart FireFox
3) Right-click search box. You'll then be given the option to add a custom search; click this, then enter the details. Finish.
4) go to firefox->settings->search and your new custom search engine should appear at the bottom of the "Default Search Engine" drop-down list. Choose it.
5) Voila!

I don't like running extensions when not in use, so I turned it off. When I restarted FireFox, my choice (google.co.uk) was still active.

Thanks @Tom Schuster

Works perfectly!

Works like a charm! I was sad when I thought Firefox didn't have something that Chrome did—but this fills that gap!

以前、Ready2Search　を長年使っていたが、提供しているサイトが閉鎖。結果、Add custom search engineに辿り着いた。Firefox内では、検索サイトをオリジナルで作れないので、今後は、オリジナルでも追加できるようにしてもらうとありがたい。しかしながら、コレはお気に入り♪

Works really well

Work perfectly.

Even if the LastUpdate dates from 2021, it still works very well in 2024 with Firefox v123.x (and maybe more than v123.x)

And please, Stop posting bad reviews without first starting to learn how to use this plugin .
All options work correctly.
Test on Firefox ESR v.x?, Firefox v123.x.x, Librewolf v123.x.x.

Thanks @TomSchuster