All copyleft software is Free software (as defined by the FSF), but not all Free software is copyleft. So it's incorrect to say that all Free software licenses

All copyleft software is Free software (as defined by the FSF), but not all Free software is copyleft. So it's incorrect to say that all Free software licenses obligate you to share your changes to the source code. Permissive licenses like MIT and BSD are also Free software licenses according to the FSF. See this explainer by the FSF: https://www.gnu.org/philosophy/categories.html https://www.gnu.org/philosophy/categories.html