Open source software is built upon the principle that end users should be given source code and should be free to use, share, modify and enhance software products, with the goal of widespread interoperability and permissive incorporation into new technology. Generally, open source products are made available royalty-free although the precise rights and restrictions imposed on open source software depend upon the specific terms of the open source license under which it is distributed. Like proprietary software licenses, open source licenses pose their own set of legal, business and technical issues for users.