There’s a number 6, where if you’re on a small team with good synergy and well experienced members, the PR is a good thing each member requests to answer the question , hey can you double check my work and please give me feedback because I really trust your judgement.it’s a no nonsense way for confident developers to get a second opinion.

This reminds me of a mod around the time of the TI-83 ish , where you had solder diodes to a cable connecting two devices.