IANAL. Legally the GPL doesn't care about proprietary or free software. What is cares about is that you license any combined works under the GPL. You could copy

IANAL. Legally the GPL doesn't care about proprietary or free software. What is cares about is that you license any combined works under the GPL. You could copy+paste the GPL, change the name and it wouldn't be a valid license for a "a work based on the Program". > You must license the entire work, as a whole, under this License https://www.gnu.org/licenses/gpl-3.0.html https://www.gnu.org/licenses/gpl-3.0.html