Sphinx documentation:

All source rendered by Sphinx is licensed under CC-BY-4.0.

You are free to:
  Share:
    Copy and redistribute the material in any medium or format.
  Adapt:
    Remix, transform, and build upon the material for any purpose, even
    commercially.

Under the following terms:
  Attribution:
    You must give appropriate credit, provide a link to the license, and
    indicate if changes were made. You may do so in any reasonable manner, but
    not in any way that suggests the licensor endorses you or your use.
  No additional restrictions:
    You may not apply legal terms or technological measures that legally
    restrict others from doing anything the license permits.

See https://creativecommons.org/licenses/by/4.0/ for full details.

This includes:
  * All ReStructured Text files:          docs/*/*.rst
  * The Sphinx configuration file:        docs/conf.py
  * Content in Sphinx-exclusive subdirs:  docs/*-guide/*


Other documentation:

There are a variety of text documents in various formats.  These, given no
explicit license guidance, fall under Xen's default GPL-2.0 license.