This is the original 1978 source code of Microsoft BASIC for 6502 with all original comments, documentation and easter eggs:
Given all this, it is safe to assume the file with the Microsoft BASIC for 6502 source originated at Apple, and was given to David Craig together with the other source be published.
Which, coincidentally, makes it quite illegal, since this code is being published without Microsoft’s or Bill Gates’ permission. Still, a very interesting look at a very crucial bit of code – at least, from an industry perspective.
You presume they didn’t buy the source outright… rather than licese it for use on thier machines.
It could be the have the right to do whatever they want with it…