Modelio source code
Direct access to project code.

So where can I find the source code?
The source code of the Modelio Modeler and Modelio modules is available on the Modelio GitHub at this address:
Modelio official GitHub
Just go to the project whose source code you want to download.
Jump station
Here are the links to some of the main project pages.
Modelio
Java Designer
TOGAF Architect