The source code for PLT is located at github.com/institutedigitalgames/PLT. Since PLT is an open-source application, developers are welcome to modify or enhance the source code via this public repository.
Besides being available as a GUI application, PLT is also available as a Python package called pyplt which is hosted on the Python Package Index (PyPi). The package offers an API with similar functionality to the GUI. For more information kindly visit pypi.org/project/pyplt.
The source code for PLT is heavily documented throughout. Additionally, the API Reference documentation may be found at plt.readthedocs.io. Moreover, the following tutorials on using PLT via the API are available: