GIMP & GEGL Made Much Progress In 2015
In 2015 much progress was made on GEGL, painting improvements were made, improved file format support happened, and much more. Lots of progress was made and can be found right now in the GIMP 2.9 test releases though it will culminate with the GIMP 2.10 stable release in the future.
For more details on the GIMP/GEGL progress of 2015, see the annual report. There were also several GIMP 2.10 articles on Phoronix in 2015 with additional details.