It's pretty straight forward.
mIRC deals with Internal Ban List with $ibl($chan,N) which returns the Nth item in the /channel list, with me?
//echo -a $ibl($chan,1) returns the first item in the ban list.
From the mIRC help file (/help Channel Central)
This allows you to view, edit, or remove various types of mode settings, such as bans, exceptions, and invites. Most IRC networks support ban lists, however few support exception and invite lists currently.
As you can see it supports Ban Lists, but few support for exception and invite lists.
Which is where $iil (Internal Invite List) and $iel (Internal Exception List) come in. Still follow? I'd imagine they'd work the same way as $ibl or atleast I hope.
Overall, it's a great suggestion I'd love to see it added.
All the best,