Between December 2011 and June 2012 GNOME successfully raised 20k$ to improve the Accessibility capabilities of GNOME.
http://www.gnome.org/news/2011/12/gnome-launches-campaign-for-accessibility/
http://www.gnome.org/news/2012/06/help-gnome-reach-its-accessibility-fundraising-goal/
http://www.gnome.org/news/2013/02/call-for-bids-for-gnome-accessibility-work/
http://www.gnome.org/news/2013/06/gnome-accessibility-bid-selected/
The work was completed by Igalia in 2015.