Or if mailbox can contain children but currently doesn't, should list "" mailbox/% show anything?
Yes, it should show the mailbox.
What about:
x list "" */%
Should it list all \NoInferiors mailboxes twice, once as "mailbox" and again as "mailbox/"? I guess no-one would really ask it, but I might as well do it right :)
IMHO, a Maildir type structure should never use \NoSelect except in LSUB.
And if a mailbox with children is deleted.
