:tree ROOT-DIR PATTERN ... a base directory and a file pattern
-:pattern DIR PATTERN ... PATTERN is a regular expression comprising path
-and file pattern -- e.g. 'PATH/^REGEXP$'. Note the `^' at the beginning
-of the file name pattern.
+:pattern DIR PATTERN ... a base directory and a regexp matching
+ files in that directory. Usually,
+ PATTERN has the form '^REGEXP$'. Unlike
+ :tree, this form does not descend
+ recursively into subdirectories.
:filter-dirs-flag BOOLEAN ... is only used in conjunction with :tree.