Forking and/or downloading this repo only makes sense:

• if you want to get a knowledge about the internals of Sikuli
• if you want to create your own packages containing Sikuli features
• if you want to contribute.

In any case: be sure you know the content of the SikuliX Quickstart

sikulix2api

the API to be used in Java and Java aware scripting languages

sikulix2 (inactive as module currently)

the Sikuli IDE and the support for running scripts in a supported scripting language.

sikulixtensions (inactive as module currently)

Packages that extend the SikuliX features in various ways.
On the usage and/or developement level they depend on the core features of sikulixapi or sikulix.

• a Java JDK 1.7+
• Maven 3+

I use NetBeans 8+ for developement.