libuv is part of the Node project: http://nodejs.org/
libuv may be distributed alone under Node's license:

====

Copyright Joyent, Inc. and other Node contributors. All rights reserved.
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to
deal in the Software without restriction, including without limitation the
rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
IN THE SOFTWARE.

====

This license applies to all parts of libuv that are not externally
maintained libraries.

The externally maintained libraries used by libuv are:

  - tree.h (from FreeBSD), copyright Niels Provos. Two clause BSD license.

  - ngx_queue.h (from Nginx), copyright Igor Sysoev. Two clause BSD license.

  - libev, located at ev/ is copyright Marc Alexander Lehmann, and
    dual-licensed under the MIT license and GPL2.

  - libeio, located at eio/ is copyright Marc Alexander Lehmann, and
    dual-licensed under the MIT license and GPL2.

  - deps/pthread-win32 is a POSIX threads library for
    Microsoft Windows and is used for the Windows build and statically
    linked into the Node executable. This software is freely available at
    http://sourceware.org/pthreads-win32/ It is Copyright 1998 John E.
    Bossom and 1999,2006 Pthreads-win32 contributors and licensed under the
    LGPL. See deps/pthread-win32/COPYING.LIB for more details.

