You can do a merge request for GEGL on GNOME's Gitlab instance:
https://gitlab.gnome.org/GNOME/gegl/.
Good. Just a question. What category (comon, comon-cxx, core, external, ...) should I put it in? Also, it includes an external .h and .c file. (I've separated the long data and enums there.) - will that be a problem? (it would be three files in total).