Of note, Charybdis (and ircd-seven aka freenode-seven), also permits flags and extraneous info in banmasks. Here are some examples.
nick!user@host$#redirect-channel
$x:nick!user@host#gecos
$r:gecos
$a:account
$~a
$j:#borrow_from_our_banlist
$x:raccoon!fuzzy@woodland.critter.net#I'm?a?little?teapot.$#you_are_banned_go_away
... but in every instance these are case-insensitive.
