However, browsers have played along with US legislation previously. (E.g., when long key encryption was restricted to US versions only.) I'm not sure, if Mozill

However, browsers have played along with US legislation previously. (E.g., when long key encryption was restricted to US versions only.) I'm not sure, if Mozilla would be playing along nowadays, but you can't be too sure, either. Moreover, you could consider certificates installed by antivirus software as some kind of prior art to this. (While considered a security risk, at least by some, they are not delisted.)