primer (https://github.com/rochus-keller/MUMPS/blob/main/docs/MUMPS_...) is an interesting read
I wish someone made something similar for Forth. Too many times I encountered something explained about forth that itself needed explanation for operators
So... it looks like this was written by Claude. I am less motivated to actually read it.
If you are a young person, under no circumstances would I recommend that you acccept a job working with MUMPS.
You won’t be able to learn the industry best practices or the modern tools, because MUMPS predates them, and your career will suffer for it.