There really isn't much to say, noattach is a milter that parses the body
of email messages from sendmail and checks if the filename of attachments
matches one of the regular expressions in a given pattern file and rejects
those emails that match.
Filenames are rfc2047 or rfc2231 decoded if needed.

This program needs sendmail version 8.12.2 or newer to be compiled with
libmilter.