In 1979, I made a program called VisiBase in this BASIC.
It's a visual database modeled after VisiCalc.
That won me a joystick in at a competition by the local computer store. :-)
Still have the source, that works in an Apple 2 emulator. It's 13 K in ASCII (untokenized).
Sadly nothing in Scott's blog post about how they obtained the source. Was it still in Microsoft's archives? Did they happen upon some tractor-feed print-outs they had to type in by hand?
It would also be interesting why it was open-sourced now. I assume if they had done the same last year, the resulting loss of revenue would not have destroyed the plucky little $3T upstart.
[1] https://www.youtube.com/playlist?list=PLowKtXNTBypFbtuVMUVXN...