This sounds like a whole lot of copium from devs who don't want to bother with the effort of just writing stuff down, ie good documentation practices...

Actually, maybe even worse (not directed at parent) - I think some "seniors" have a stick so far up their err keyboard, and think they are so wise beyond words that they refuse to share their "all knowing expertise" with anyone else as a form of gatekeeping or perhaps fear of being "found out" (that they are not actually keyboard "Gods").

Really though, just wright shit down even if the first draft isn't great. Write it down, check it into the codebase.