The Drag[en]gine Shared Launcher Library source code is available under the L-GPL or GPL license as you desire. This library allows to write Launchers according to the GLEM System. Launchers are responsible to launch games in the *.delga format. See the “GUI Launcher” in the Drag[en]gine repository as example of how to write a launcher.

Drag[en]gine Shared Launcher Libary API Documentation