A major part of the Symbolic variant icons are a derived work from the
art-libre-symbolic theme made by the GNOME design team (mostly by
Barbara Muraus and some work by Jakub Steiner as far as we know), taken
in its 2015 form and modified since (including new icons, modified ones,
possibly removed ones):
https://github.com/gnome-design-team/gnome-icons/blob/master/art-libre-symbolic/src/art-libre.svg
All icons (modified or not) taken from the art-libre-symbolic theme are licensed
under the Creative Commons Attribution-Share Alike 3.0 United States License.

A few more Symbolic icons are taken (e.g. gimp-lock) or derived (gimp-lock-*)
from the Adwaita icon theme as Creative Commons Attribution-Share Alike 3.0
United States License as well.

The Color icons are more of an original work with inspiration from other FLOSS
themes. These icons, as well as all new icons (both in Symbolic or Color
variants) are licensed under the Creative Commons Attribution-ShareAlike 4.0
International License.

To view a copy of these licenses, visit either:
http://creativecommons.org/licenses/by-sa/3.0/ or
http://creativecommons.org/licenses/by-sa/4.0/ respectively or send a letter to
Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.

When attributing the artwork, "GIMP team" is enough for icons which were fully
created for GIMP. For icons taken and modified from the GNOME design team,
attribute them to "GNOME Project" and "GIMP team".

Please link to https://www.gimp.org/ where available.
