Hugo asked for the API documentation,
not a getting started, but I did not realize you needed
documentation on how to include a jar into a Java project. Luckily
Google has information on that.
http://stackoverflow.com/questions/3280353/how-to-import-a-jar-in-eclipse
For the rest, each class has a description on how to use it, like,
for example, agenda. But of course you knew that, because you read
our documentation before voicing an opinion.
http://jfxtras.org/doc/8.0/jfxtras-agenda/index.html
Is the the perfect amount of documentation? No. There can always
be more, it is a matter of choosing where to spent one's free time
on. ControlsFX, which you kindly swipe under the same rug as
JFXtras, has invested a lot of energy in their documentation,
including a "getting started" which you apparently need so much.
But you of course know this already, because you read that before
voicing an opinion.
http://fxexperience.com/controlsfx/
But, out of pure curiosity... What is your open source
contribution to the world?
Tom