Gecko (the engine that Firefox uses) isn't really meant to be embedded, and Mozilla stopped supporting that usecase a while ago. It's more like you have to design your app around Gecko, with XUL, which essentially makes Gecko both a browser engine and a UI toolkit.
i remember back when the app wouldn't watermark downloaded images so 12 year old "memelords" on r/dankmemes would manually add watermarks to their cringe-ass memes to prevent Instagram accounts from "stealing" said memes
god, leaving reddit has made me realize just how much of a cesspool it was. i can't believe people actually called themselves "redditors".
Most of that is about Exchange. Because Microsoft software is always garbage.