Erm. I've been a developer for... well, certainly longer than most people on HN, I've reviewed code for most of that time, and for most PRs/MRs, I read the code almost linearly. I take a few notes here and there, and sometimes return to amend my notes, but that's often it.

It's only when a PR reaches a fairly high complexity (typically a refactoring, rather than a new feature) that I take the effort to sort it any further.

So, yeah, I guess I'm pleading guilty of doing that? But also, in my decades of experience, it works for me. I'm sure that there are other manners of reviewing, of course.