GNS3 GUI repository.
If you want to update the interface, modify the .ui files using QT tools. And:
If you want to see the full logs in the internal shell you can type:
Or start the app with --debug flag.
Due to the fact PyQT intercept you can use a web debugger for inspecting stuff: https://github.com/Kozea/wdb
If you want to simulate a user with PyQT4: