Has anyone made a Chrome/Firefox extension that adds a button to any non-"home" kbin/lemmy instance magazine that lets you subscribe to it?

Basically, I want to be lazy and be able to click "subscribe" on any magazine/lemmy version of magazine in the threadiverse without manually changing the url to kbin.social/m/whatever@blah.tld.

Has anyone written such a browser extension already? (And if so does it support Firefox?)