The list of available usermodes:

a: services admin, allowed to /samode
A: server admin, allowed to use /mod*
i: the user is invisible
o: operator, allowed to /kill,/kline,/gline
r: registered
R: the user does not want to get messages from unregistered users
w: channels are hidden in /whois
x: the user hides their hostname
t: Translation mode
