“mold started as my personal project, and I’ve been working on this full time for two years so far.”
Mold is the fastest linker around, and corporations use it to shave minutes off every build. Rui Ueyama has worked on it full time for two years and the donations don’t cover it. So individuals stay free and companies pay. Open source purists will howl. The companies saving millions in CI time could have just paid him.