license_type
Description:
The license of the program, as a value of the gtklicense enumeration.
The AboutDialog will automatically fill out a standard disclaimer and link the user to the appropriate online resource for the license text.
If gtk_license_unknown is used, the link used will be the same specified in the website property.
If gtk_license_custom is used, the current contents of the license property are used.
For any other License value, the contents of the license property are also set by this property as a side effect.