https://github.com/irchelp/irchelp.github.io/blob/3a33c4210baa62eac18ca7ed90fa9c22da634f57/clients/unix/ircii/irciiman.txt#L1738

I think Irssi accepts it with and without S

we can still change it I'm kinda indifferent here

Any unambiguous prefix works but I would expect the complete form in documentation.

upon second thought, the correct form should probably be the one listed in https://github.com/irssi/irssi/blob/master/src/core/levels.h

the whole affair is a bit unfortunate I'm afraid

If this means we need to pretend the two lists are the same or that this primarily describes the scripts interface then there should be some hint about that or that will keep tripping people up IMO.

Up to you of course what you want to commit but I would at least be consistent in the examples. It's confusing to see PUBLIC and PUBLICS in /help ignore.

I think it should be changed to PUBLIC everywhere, one way to do this could be to add some sort of special case to the bits2level function