Of course, there's no fool-proof solution to knowing what code is running in the server side, but https://searx.space https://searx.space at least shows if an i

Of course, there's no fool-proof solution to knowing what code is running in the server side, but https://searx.space https://searx.space at least shows if an instance modified their client-side code, which you can see in the HTMl column. To mitigate server-side code from identifying you, you can consume an instance from Tor. Of course, you could try to do that with any other search engine, but most of the other search engines either block exit nodes or provide incomplete functionality if you disable JS. It's not perfect, but it may be good enough depending on your threat model.