GNS3 GUI repository.
Please see https://docs.gns3.com/
If you want to update the interface, modify the .ui files using QT tools. And:
cd scripts
python build_pyqt.py
If you want to see the full logs in the internal shell you can type:
debug 2
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
Please contact us using contact informations available here: http://docs.gns3.com/1ON9JBXSeR7Nt2-Qum2o3ZX0GU86BZwlmNSUgvmqNWGY/index.html