Most distributed software can be categorized according to their license type (see table). There are several organizations in the FOSS field that publish guidelines and definitions for software licenses. Free Software Foundation maintains non-exhaustive lists of software licenses based on its definition of free software and licenses that the FSF considers non-free for a variety of reasons.  The FSF also distinguishes between free licenses of software compatible or incompatible with the FSF license of its choice, the Copyleft GNU General Public License. The Open Source Initiative defines a list of open source licenses certified according to their open source definition.  The Debian project also has a list of licenses that follow debian guidelines for free software.  Unauthorized software outside copyright protection is either public domain software (PD) or undelated, unauthorized software and treated as an internal trade secret.  Contrary to popular belief, unlicensed (non-public) software is fully protected by copyright and is therefore legally unusable (since no right of use is granted by a license) until it is transferred to the public domain at the expiry of the copyright clause.  For example, these are unauthorized software leaks or software projects placed without a specific license on public software repositories such as GitHub.
 Since the voluntary transfer of software to the public (before reaching the copyright clause) is problematic in some jurisdictions (z.B.dem German law), there are also licenses that grant type rights, such as cc0 or WTFPL.  A software license is a legal instrument (usually in contractual law, with or without printed material) that regulates the use or transmission of software. Under U.S. copyright, all software is copyrighted, both in source code and object code, unless the software has been developed by the U.S. government, in which case it cannot be protected by copyright.  Authors of copyrighted software may give their software to the public, in which case it is not copyrighted and therefore cannot be authorized. Many proprietary or open-source software companies sell the copy of the software with a license to use it. There is no transfer of ownership of the thing to the user who does not guarantee lifetime availability of the software, nor is allowed to sell, rent, give to someone, copy or redistribute. Licensing terms may define other legal clauses that users cannot negotiate individually or through a consumer organization and that can clearly accept or reject the product by returning the product to the seller.  This right can be applied effectively if the court provides for a binding deadline for a good reduction immediately after the purchase (as in EU law) or a mandatory public public advertisement of the licence conditions to be made readable by users before the purchase.