proletext   (link)

http://www.templetons.com/tech/proletext.html
Invisible formatting information is embedded in trailing spaces and tabs on the ends of lines in an ordinary looking document. In addition, "blank" lines contain spaces and tabs with hidden formatting meanings. Assuming typical 60 column lines, one can have over 300 different codings on the end of a line without going past 80 columns. (Far fewer are needed.) On a blank line, almost a billion codings are possible.

Documents with invisible formatting always start with a magic line, which begins with "" followed by version encoding. Thus documents can be spotted and formatted even without a Mime Content-Type header for this new text type. This otherwise useless combination of spaces and tabs on a blank line should virtually assure that random documents are not treated as formatted.

found this from a link in on of the ACME modules on CPAN...