This is GTK+ version 0.99.6.   GTK, which stands for the Gimp ToolKit, 
is a library for creating graphical user interfaces.  

The official ftp site is:
  ftp://ftp.gimp.org/pub/gtk

The official web site is:
  http://www.gimp.org/gtk

Patches can be uploaded to:
  ftp://ftp.gimp.org/incoming

A mailing list is located at:
  gtk-list@redhat.com

To subscribe: mail -s subscribe gtk-list-request@redhat.com < /dev/null
(Send mail to gtk-list-request@redhat.com with the subject "subscribe")