Greetings!
You can find the latest markdown versions of our user docs in our git repository:
https://github.com/nvaccess/nvda/tree/master/user_docs.
However, this might not be helpful, as we use our own custom syntax.
There are many different "flavours" of writing markdown, depending on the tools you are using.
We use a custom version with custom tooling.
If you are not looking to contribute to NVDA, but rather create your own markdown files, I would focus on that and not involve or think about NVDA markdown at all.
Instead, I would suggest using a browser based markdown editor such as
stackedit or
markdown2html to learn and create markdown files.
Since this is off-topic to NVDA, I am locking this thread, but feel free to email me directly if you have further questions and I'll try to respond on my own time outside work hours.
Cheers,
Sean
NV Access