I need to change printrating method in rating.php but I don't know where rating.php is located... is there a file location reference page? (reason for change is that the button text does not translate for me)

That would be in the rating plugin naturally.

That's what I thought too, but when I go to
/zp-core/zp-extensions/rating

I don't see it there...?

and there is no rating folder in /plugins.

You should probably read the document on plugin architecture. Did you perchance happen to see /zp-core/zp-extensions/rating.php?

Ah there it is, thanks.