- A list of file and directory names, without path, that will not
- be searched for messages by **notmuch new**. All the files and
- directories matching any of the names specified here will be
- ignored, regardless of the location in the mail store directory
- hierarchy.
+ A list to specify files and directories that will not be
+ searched for messages by **notmuch new**. Each entry in the
+ list is either:
+
+ A file or a directory name, without path, that will be
+ ignored, regardless of the location in the mail store
+ directory hierarchy.
+
+ Or:
+
+ A regular expression delimited with // that will be matched
+ against the path of the file or directory relative to the
+ database path. Matching files and directories will be
+ ignored. The beginning and end of string must be explictly
+ anchored. For example, /.*/foo$/ would match "bar/foo" and
+ "bar/baz/foo", but not "foo" or "bar/foobar".