Hi Alan

I know that you are continuing to work hard on annotations in the TTG extension fields -- thank you.

As you know, I'm very eager to get a big Note to explain how it all works.  At the moment I am completely lost, and I am reduced to cargo-culting code by copy/pasting and hoping for the best.  Plus we are over-reliant on you, which isn't really fair on you.

Several of us (including me and Rodrigo, and doubtless other ghc-devs, cc'd) would be happy to review, edit, and improve -- but it is hard for us to see the "big picture".

Could you see your way to drafting something? It need not be that long initially, but having *something* to ask questions about and improve would be super helpful.  

I suggest drafting it in a Google doc so it was easy to edit, and for others to contribute to, but ultimately it should be in the repo. 

Thanks!

Simon