Xerox PARC source code (via info.computerhistory.org).

This archive is a collection of source code and digital text documents, image files, and other files from Xerox Palo Alto Research Center (PARC). This came from the same IFS backup file repositories that the earlier 2013 release of the Xerox Alto source code archive came from, and is a superset of that archive, containing files related to projects from the 1980s, up to 1994, that were not included there.