More than likely, they're GNUzip files. It's a compression format from the Free
Software Foundation (GNU) folks, and has two basic features: no LZW compression
like UNIX "compress", hence, no Unisys patent problems, and free programs for
most every platform, usually called gzip and gunzip. gunzip also uncompresses
UNIX compress files (*.Z), since the Unisys patent only covers LZW encoding and
not LZW decoding.
-- -Brian Smithson brian@grot.starconn.com