When I was an - intern 30 years ago - the senior developer working with me had to decide if my code was worth a "formal review" or if just putting it in code review was enough. We went to code review, but as part of this I did hear about a process where code reviews are useful that apparently the company did use for important/difficult code.
In a formal review you print off the code, then put 5-10 other developers in a meeting room to look at it together (no computers in this room, though sometimes you would go back and print off some more code for context). You could do about 10 lines of code per hour this way, and the developers burned our after at most 2 hours per day, so this takes a very long time. However reports were this resulted in the most useful reviews/fixes to the code.
I've never seen the above done in practice, just heard about it. Someday I'd like to see it, but I doubt I ever will.
That sounds like a Fagan review. I haven't been involved with one either, but I think some of the forces that drove people to do them have been weakened.
When you are shipping code that you won't be able to update easily (i.e. cheaply), you try to remove as many defects as early in the process as possible. CI/CD and web delivery seem like they would blunt the motivation to go through a Fagan review for most software developed these days.
I would imagine that some form of this still happens in safety-critical systems (or more likely the state of the art has advanced from this).
In a formal review you print off the code, then put 5-10 other developers in a meeting room to look at it together (no computers in this room, though sometimes you would go back and print off some more code for context). You could do about 10 lines of code per hour this way, and the developers burned our after at most 2 hours per day, so this takes a very long time. However reports were this resulted in the most useful reviews/fixes to the code.
I've never seen the above done in practice, just heard about it. Someday I'd like to see it, but I doubt I ever will.