It is a touchy subject and I have never asked. I think they want to improve Epiphany a little and I may push to include it when the entire image is ARMv7 and there is no support for the Pi1 and Pi0.
I'm not sure if anything may happen at all. No software for which the collabora people are responsible (including epiphany, webkit3 engine,parts of gstreamer1.0) has been fixed for many months. I reported a serious bug in gstreamer1.0 in October last year and nothing has happened so far. And many of the bugs and memory leaks in webkit3 and modules used by it are known for a long time now.
In fact, only one bug (in gst-omx) has been fixed but only after I had sent them the fix myself.