I was searching the web for examples of other implementations of M query, but didn't find any. So I concluded that Power Query is Microsoft's proprietary IP. I am asking this question because it would be tempting to develop a data service which is capable of executing M Query scripts. If anybody has concrete information what the licensing status of M query is, I would greatly appreciate your feedback.
Regards B
Microsoft's implementation is not open source.
The language specification is publicly available, however.
The API for the standard library is also publicly listed.