Build with enough clarity that future contributors know what deserves protection.

Anyone who takes over something will change parts of it, and without guidance they cannot tell which parts are load-bearing and which are accident. So they preserve arbitrary details and remove the things that mattered. The failure is not theirs. Nobody told them where the weight was.

Make explicit what must not change and why. A short list of the non-negotiables, with reasons, is worth more than pages of description. It lets people improve confidently instead of carefully.