Not far off releasing the next version, but wanted to get peoples' thoughts on it first.

Its based on the 010 Editor Binary Template syntax, but with some changes, hopefully the manual pages here give a clear idea of how it works... let me know if there's anything missing!

Oh yeah. There's a manual now. The same source used to generate this online one also generates a traditional in-app manual (chm on Windows, wxWidgets equivalent on Linux/Mac).