Short version for non-lawyers: This project is dual-licensed under Apache 2.0 and MIT terms. Longer version: This library contains code derived from the Rust Project. The modifications are copyright 2014, Mikhail Zabaluev . The Rust Project is copyright 2014, The Rust Project Developers (given in the file AUTHORS.txt). Licensed under the Apache License, Version 2.0 or the MIT license , at your option. All files in the project carrying such notice may not be copied, modified, or distributed except according to those terms. Additional copyright may be retained by contributors other than Mozilla, the Rust Project Developers, or the parties enumerated in this file. Such copyright can be determined on a case-by-case basis by examining the author of each portion of a file in the revision-control commit records of the project, or by consulting representative comments claiming copyright ownership for a file. In all such cases, the absence of explicit licensing text indicates that the contributor chose to license their work for distribution under identical terms to those Mozilla has chosen for the collective work, enumerated at the top of this file. The only difference is the retention of copyright itself, held by the contributor.