How do I change the format/ display of the list of mailboxes/ folders (or any menu)?
The default display of mailbox folders includes a lot more information than sometimes needed. It is “N permissions owner group size date name” but you might prefer something shorter like “N size date name”. You need to adjust the $folder_format variable to configure the look of the display of available inboxes (browser), look it up in the manual.txt. In general, you customize views with the *_format set of variables, there are some of them.