CP/M is really open-source now
Bryan Sparks, President of DRDOS, clarified the license of CP/M: Let this paragraph represent a right to use, distribute, modify, enhance, and otherwise make available in a nonexclusive manner CP/M and its derivatives. This right comes from the company, DRDOS, Inc.'s purchase of Digital...
retronic.us
Rather than a formal license, it's a clarification from Bryan Sparks about the status of CP/M source code.
A real license would be better, who knows if that's forthcoming.
But the intent from the post is at least clearer as to the status of CP/M source code and its distributability.