Source code release by Bill Gates, April 2, 2025

[markjenkins]

Bill Gates released scans of his source print out on April 2, 2025
https://www.gatesnotes.com/microsoft-original-source-code

No license was provided.

GitHub user MaiZure has a study project
https://www.maizure.org/projects/decoded-altair-basic/

There's a few versions of the listing
https://github.com/MaiZure/AltairBASIC/blob/main/ALTAIRBASIC30.LST
https://github.com/MaiZure/AltairBASIC/blob/main/ALTAIRBASIC30_ASM_LINES.LST
https://github.com/MaiZure/AltairBASIC/blob/main/ALTAIRBASIC30_ASM_NOLINES.LST

This all came to my attention in September 2025 as Microsoft released 6502 Basic under FLOSS terms which was a port of the Altair basic:
https://github.com/microsoft/BASIC-M6502