I can't find the auto-complete api of some search engines

Greeting, first of all, I’m a Firefox Android user. Your problem is this; I’m trying to understand and find the auto-complete urls (we can say API) of search engines like Startpage, Yandex. I tried to look at the files in the “searchplugins” folder, but all failed. I haven’t found much on the Internet about this topic, I hope you can help me.

It took me a long time…


Sorry, you can go on.