Nothing really implemented it properly or checked for it and the places that did check just handled it as a slightly softer ban.
It's pretty obvious that the existence of this feature was directly taken from osu! where the differentation between a ban and a silence probably makes more sense, though even there Silences are just non-permanent bans, so like why does this exist lol?
Well, it doesn't anymore! Hopefully chat will upgrade successfully because I let it get 18 commits behind :D