Hmmm no free software can be closed source. Neither is the subset of the other but they intersect
Free software, as defined by the fsf, preserves the users freedom to study, change and distribute the software. The right to study entails that the source code be made available: Wikipedia article. Calibre is licensed as GPL3, thus it is free software as defined by the fsf.
You're absolutely correct. Not to be confused with freeware which is more ambiguous and most often proprietary (though not always).
Hmmm no free software can be closed source. Neither is the subset of the other but they intersect
Free software, as defined by the fsf, preserves the users freedom to study, change and distribute the software. The right to study entails that the source code be made available: Wikipedia article. Calibre is licensed as GPL3, thus it is free software as defined by the fsf.
You're absolutely correct. Not to be confused with freeware which is more ambiguous and most often proprietary (though not always).
https://en.m.wikipedia.org/wiki/Freeware