Where is the nifty gui docs?

General Discussion
1

where is the nifty gui docs?
Im looking for how to write a custom control ?

2

Here:
https://sourceforge.net/projects/nifty-gui/files/nifty-gui/1.3.2/
nifty-gui-the-manual-1.3.2.pdf

Valid for JME 3.0. But also for JME 3.1 even the Nifty is 1.4.1 (1.4.2 on master).