gtk2-ng.svg is based on File:GTK.svg from Wikimedia Commons.

Source:
https://commons.wikimedia.org/wiki/File:GTK.svg

Original source:
Conversion of Image:GTK.png to SVG using Inkscape.

Author:
Jose Hevia, vectorised by DTR at English Wikipedia.
Commons cleanup by Tene~commonswiki.

License:
Creative Commons Attribution-ShareAlike 3.0 Unported or
GNU Free Documentation License 1.2 or later.

This copy is included under the Creative Commons Attribution-ShareAlike
3.0 Unported license.

No endorsement by the original authors or Wikimedia Commons is implied.