Please see the User Manual found at http://graspit-simulator.github.io/ for an introduction to GraspIt!, a list of features, installation instructions, getting started examples, etc.

GSL-GNU Scientific Library; for the use of random sampling https://www.gnu.org/software/gsl/

CMakeLists.txt: Used to compile GraspIt!, multiple flags that can be set with ccmake.
CMakeMacros: contains .cmake files used to find GraspIt! dependencies.
cmdline: command line parser used by GraspIt!.
ci: contains scripts used by travis ci.
doc: Documentation. Contains both the User Manual and code Reference Manual. The User Manual contains installation instructions, pointers for getting started, examples, and trouble shooting and contact information.
images: A place to put images saved from GraspIt!
include: Header files for the main GraspIt! source code
LICENSE.txt: A copy of the license you accepted when you downloaded this.
models: The geometry and configuration files for all the robots and objects.
plugins: Examples for creating plugins that can be loaded into GraspIt! at run time, and can use GraspIt! without being statically linked into GraspIt's main executable.
ply: Code for loading .ply files; see header files for authorship information and detail.
qhull: A popular package for computing n-dimensional convex hulls. This is used both for the contact system and to create grasp wrench spaces.
README.md: This file.
src: The source code for GraspIt!.
src/DBase: source code for the interface between GraspIt and the Columbia Grasp Database
tinyxml: a library for processing XML documents. See the header files therein for license and author information for this package.
ui: The dialog windows and interfaces for GraspIt!.
worlds: A place to save GraspIt! worlds. Also includes a few examples.

https://github.com/JenniferBuehler/graspit-pkgs
https://github.com/curg/graspit_interface
https://github.com/ros-interactive-manipulation/graspit_simulator
https://github.com/OSUrobotics/graspit_ros_plannings