[Dismas]

I don't know if I'm being dumb, but I don't understand how this has anything to do with fonts? Unless it's more to do with it being a third party?

Google's font library is used on websites. When a developer uses Google's public font library on their website, they are often embedding Google's resources. Since visitors load these resources when they visit the webpage, they are inadvertently connecting to Google (and disclosing their IP). This can be avoided by hosting fonts locally, but the larger issue is that Germany is trying to hold people responsible for embedding 3rd party resources.