Well the version number make sense.
The C64 and the C128 was 8-bit home computers made by Commodore. Each named after the amount of memory it have.
Commodore 64 - 1982
Commodore 128 - 1985
Commodore Peripheral Bus - 2019: Part 1: IEEE-488 and 2: Bus Arbitration, TALK/LISTEN, Part 3: Commodore DOS, 4: Standard Serial, 5: TCBM
Rich Code for Tiny Computers: A Simple Commodore 64 Game in C++17 - 2016
A Full C64 Game - In 2013
Commodore 64 assembly programming in Windows - 2011
25c3: The Ultimate Commodore 64 Talk - 2010
Displaying Commodore 64 Graphics in BASIC and Assembly - 2021