No clear way to apply font styles, but multiple ways to break things

I have to..detach a font pack for a url..? The url it gives me doesn't work in any of the URL link boxes...nothing about this is intuitive.

I can delete a font style with no warning, but actually using a font style is a dead end. (https://fonts.gstatic.com/s/quicksand/v37/6xK-dSZaM9iE8KbpRA_LJ3z8mH9BOJvgkCEv18G0wx40QDw.ttf) What do I do with that? According to your font packs, this isnt a url 🤷