This is the original source code for the IBM CP/67 CMS operating system from 1973.
The source is in assembly listing format as produced by the S/360 assembler for CP/67.
This source code was recovered from tape reels found in a dumpster (literally!) and then converted to digital .aws format. The format is in very told VM TAPE format not directly usable on today’s z/VM (which is the grand-grand-grandchild of CP/67). So I read the tapes into VM/370 which is still close enough to CP/67 to be able to read the tape format.