I'm not against the addition of those to the help file, I was just trying to find a rational reason as to why it's not there already.
Don't get me wrong, what you reported is indeed a bug, it just need to be fixed. I'm not saying those unrealircd server provide a broken 005 raw, they just don't provide a prefix for the mode, mIRC works as good as it can for unrealircd. There is no need to change the current behavior, just a need to fix this bug.
