Any change should involve two people that are familiar with CPython.
Experts should get a change to get involves, either on the BPO or PR.
The second person doesn’t have to be a core dev. It could be a trusted reviewer, an aspirant, or an established expert from our community. On some occasions I have asked engineers for a review on SSL related stuff that don’t even use Python.
The expert doesn’t have to do the entire review. “Conceptual review” is the term I was looking for, thanks!