+.br
+cthe optional \fB{\fP\fIlanguage\fP\fB}\fP means that the tag should be
+created only for files of language \fIlanguage\fP, and ignored
+otherwise. This is particularly useful when storing many predefined
+regexps in a file.
+.br
+In its second form, \fIregexfile\fP is the name of a file containing
+regexps, one per line. Lines beginning with a space or tab are assumed
+to be comments, and ignored.