Quick and non-essential fix for next release - thanks
osTicket Version v1.15.4 (6bd7884) Admin -> Emails -> Emails: {url}/scp/emails.php?id=2
The help popup for "Mail Folder" reads "emtpy" instead of "empty"
I create a PR to fix the spelling error. This is something that you could also do yourself.
https://github.com/osTicket/osTicket/pull/6032