The software is available under the GNU General Public License (version 3 or later), which allows you to study and modify the software as much as you please.
The software has been developed on Linux, but also works on Mac OS X 10.6 with Xcode 3.2.6. Compiling the library requires at least gcc version 4.2.1. The tracker depends on several standard libraries, that you need to install in order to compile the tracker. These are
On Linux these should be easy to install using the system package manager and on OS X all relevant libraries can be installed using MacPorts.