I love this add-on, it does what I want, except I'd like to change the default search engine path in order to remove commercials, change locale etc. but it seems not possible - or at least difficult since I can't figure out which files I need to edit.

It changed my search engine, which is what I wanted. But it also changed my start page, and I didn't want that. There was no option to make it not change my start page.

So I uninstalled it.