Open but not free is what Microsoft and others do/did in some projects. That's one of the reasons why Stallman is so eager to draw the line between open and fre

Open but not free is what Microsoft and others do/did in some projects. That's one of the reasons why Stallman is so eager to draw the line between open and free software. Example: Java's stdlib source code is open for you to read it but you're not free to modify it and redistribute it according to your likings. (A few) People pay developers of free software to get support (e.g. some libs), for professional editions (e.g. some IDEs), or to support further development (e.g. some Android apps).