Actually, I’ve got to add another note because my memory and experience was insufficient here: see also https://en.wikipedia.org/wiki/IDN_homograph_attack#Clien

Actually, I’ve got to add another note because my memory and experience was insufficient here: see also https://en.wikipedia.org/wiki/IDN_homograph_attack#Client-side_mitigation https://en.wikipedia.org/wiki/IDN_homograph_attack#Client-si... for descriptions of what further restrictions browsers do, with the most notable additional filter being disallowing mixing scripts. This is something that would be nice to formalise in some way, though I don’t know of any venue suitable for the task.