This is 00readme in /pub/categories/96 

The files in this directory each contain messages from one month
of the categories mailing list e.g. 96-3 is from March 1996.
Each message within a file begins with a header containing at minimum
"Date:"
The date, sender and subject lines of postings are in the files
dir.*  in this directory.

File updated:
6 April 1996