Short version for non-lawyers:
The Rust Project is dual-licensed under Apache 2.0 and MIT
terms.
Longer version:
Copyrights in the Rust project are retained by their contributors. No
copyright assignment is required to contribute to the Rust project.
Some files include explicit copyright notices and/or license notices.
For full authorship information, see the version control history or
https://thanks.rust-lang.org
Except as otherwise noted (below and/or in individual files), Rust is
licensed under the Apache License, Version 2.0 <LICENSE-APACHE> or
<http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
<LICENSE-MIT> or <http://opensource.org/licenses/MIT>, at your option.