Published schematics go back to the earliest days of radio. Electronics magazines and the Radio Amateur's Handbook are roughly a century old.

Before that, there was science. Although the rules were loosely defined, scientists were expected to provide enough detail in their papers for someone else to replicate their work. That's where I learned about open design, before I learned to program.

Into the modern age, when "code" became part of electronics projects, the magazines printed source code listings, and later required authors to provide their code for an online repository. I published a couple of those articles back in the day.