This is the same behavior as the regular browser, but I think still
deserves a quick mention.
Thanks to Charles for pointing out this section of the manual and
suggesting the addition.
<quote>IMAP</quote>, possibly followed by the symbol <quote>+</quote>,
indicating that the entry contains both messages and subfolders. On
Cyrus-like servers folders will often contain both messages and
-subfolders.
+subfolders. A mailbox name with a trailing delimiter (usually
+<quote>/</quote> or <quote>.</quote>) indicates subfolders.
</para>
</listitem>
<listitem>