The Kicad revision inspector allows you to diff your pcb projects against the git log to see where you went wrong.

Some common pitfalls in C/C++ and ways to avoid undefined behavior, illustrating that C/C++ are optimized for speed by making a concession that is undefined behavior. This makes these languages tricky to write in well, as there are lots of pitfalls. Do you think the performance benefits outweigh the brutal learning curve?

There's a lot of old software available through this. Truly a work of art.