The man.zip file contains all the Minix manual pages as found in /usr/man.
They should not be in this ZIP format, please use

	pkunzip -d man.zip

in an empty directory to extract the ZIP file.  The -d is important, it
keeps the directory structure.  The usage(8) manual can be found in
cat8/usage.8.  You may want to copy that file to a more prominent location.
--
								Kees.
