Are there any docs, or even just a list of changes you've made to NI? The latest version (from Jon's site) that I have is 1.32.
Jon made a lot of changes between 1.32 and 133b19 (even between the two beta versions I had).
My own changes are pretty minor: fixed fields for IWD1/2 that were either incorrect or "Unknown". I can give you more details if you want, but I think the larger set of changes are from Jon.
The only other larger addition I have is NIDigGen which is a command line utility. This lets you dump text versions of game resources (SPL, CRE, ARE, etc) including all sub-structures fully expanded. This is very useful if you want to brose or grep through resources for things without having to deal with a lot of windows.