Polkadot relay chain node source code walkthrough/explanation

Question

Is there any documentation/tutorials covering the technical details behind the Polkadot relay chain source code, specifically the runtime where all the special logic of the relay chain occurs? I am referring to the code in this repo: https://github.com/paritytech/polkadot. So far, the tutorials I have found mainly deal with creating new blockchains with Substrate.

For instance, if I was trying to change the relay chain such that parachains don't need to be auctioned off and can only be used by people with the admin (sudo) key, I would need to understand how the relay chain source code works and is organized. Any resources are greatly appreciated!

Answer 1

The Web3 foundation maintains a detailed specification doc of both the polkadot host and the runtime, you can it find it here. However, note that this document may be outdated in certain sections, the source of truth is always found in the current release of the runtime.

Moreover, note that Polkadot is built with Substrate, hence Substrate tutorials and doc covering the Sudo pallet will be relevant to your concrete example.