If i'm gonna untangle something, i may as-well write some notes. If i'm writing notes on it already, i may as-well refine the grammar a bit and update the docs. It's really quite small effort compared to the main work of learning the system, so i don't quite get why so few people do it.

I think you are misreading the parent comment here.

I'm ... confused what you mean. If the junior is gonna untangle the docs anyway, why not make them directly update the parts that confused them once they're through it.

They're not necessarily prohibited from asking questions if they're stuck, though. But also search in the chat channels for similar issues.

Updating docs in source control also onboards folks to code review. It would be weird to update docs and get a hostile reception.

While nice to walk through with someone and conduct a usability study, just leave it better for the next person (who could be yourself, if you forget). That has happened before.