The easiest place to read it is here: http://tools.ietf.org/html/draft-kelly-json-hal
Please contribute proposals for changes that you think will improve the spec!
Simple:
Edit either the txt or the xml file, whichever one you want - and submit as a pull request.
Wonk-mode:
The txt is actually generated from the xml so it's better if you edit the latter. You also get extra brownie points if you:
- install xml2rfc (
pip install xml2rfc) or use https://xml2rfc.tools.ietf.org/ - generate the txt from the xml
- submit both in your PR