In my journey getting started with the emonPi, I’ve asked a number of questions and received some great answers. Thank you!
I’d like to start contributing back to the community by helping to improve the documentation, to clarify areas that are missing some useful information, which might help people like me in the future. Is there a process to do this? Is there documentation on the documentation? 
In short - no.
We all know that there’s a lot to be desired regarding all aspects of documentation, I revised a lot of “Learn” about 12 months ago, but stopped for reasons that I’m not prepared to discuss on a public forum.
My one over-arching comment - once you’ve realised that like Topsy, it just grew and grew - I think would be the presentation (in the widest possible terms) wasn’t designed with the new, or indeed any, user in mind.
You’re welcome to try, but if you give up when you realise the enormity of the task, I’ll be sympathetic but not surprised. You won’t be the first, I’m afraid.