SOURCE

You can get a copy of the source code for these error documents at
https://github.com/TheRealOne78/error_pages/.


TERMS OF USE AND LICENSING

All HTML (HyperText Markup Language), CSS (Cascade Style Sheets) and JS
(JavaScript) code is licensed under the terms of GNU GPLv3+. You can find a
copy of the GPLv3+ license at './LICENSE.GPL3' or at
https://www.gnu.org/licenses/gpl-3.0.en.html. If you are unable to find the
license, contact the Free Software Foundation at <licensing@gnu.org>.

All images including the ones in the SVG format are licensed under the Creative
Commons Attribution 4.0 International (CC BY 4.0), except for the images in the
'/img/license/' directory which are made by the Free Software Foundation and
Creative Commons. To view a copy of this license, see './LICENSE.CCBY40' or
visit http://creativecommons.org/licenses/by/4.0/ or send a letter to Creative
Commons, PO Box 1866, Mountain View, CA 94042, USA.

All the other used assets are used under the Public Domain and are written in
the "List of other assets and authors" list.

Since the error documents are licensed under the GNU GPLv3+ license, when you
modify the error pages, you have to comply with the license - you can integrate
software that is permissive, but not the other way. For example, you can't add
proprietary JavaScript code, but you can add (free and) open source JavaScript
code that is compatible with the GNU GPLv3+ license.

Even if the error documents are licensed under the GNU GPLv3+ license, you can
still deliver non-free resources as long as the error documents and the other
resources don't interract with each other when delivering to the client. When
the client will have the error documents delivered, the host must not deliver
resources that are not compatible with the GNU GPLv3 license.


LIST OF OTHER ASSETS AND AUTHORS

* /fonts/VT323-Regular.ttf - by Peter Hull, licensed under the Open Font
    License, taken from https://fonts.google.com/specimen/VT323;
* /img/license/by.svg - by Creative Commons, licensed under the Creative
    Commons Attribution 4.0 International (CC BY 4.0) license;
* /img/license/gpl-v3-logo.svg - by the Free Software Foundation for the GNU
    GPLv3 license, available as public domain.