Solana has no single document that sets out its protocol rules. They are spread across years of improvement proposals (SIMDs) and the code of its validator clients.
@anza_xyz's Brennan Watt (
@bw_solana) has proposed one living Solana protocol spec instead: each change becomes a pull request against it, merged only when the change goes live on Mainnet.
He has already posted an 18-chapter draft. It is a proposal for feedback; nothing has been adopted.