That's a neat site. Does that mean there are no public/surviving original comments of the C64 BASIC and kernal?
My references (35 years) ago were some books published by Data Becker GmbH.
Note also that there were basic extensions to address the limitations of CBM basic like the Simon basic cartridge.
That Simon basic was a wonder in their own. Written by a gifted teenager and extending by mapping addresses in the ROM. It was possible to write sprites and graph in basic without pokes (no ASM needed).
Edit: I missed the comment downthread that says that some of that code was released a couple of years ago.