Created attachment 468758 [details] gdb (bt full; c).txt Epiphany Technology Preview 45.0-61-g3b334ba2c+/ WebKitGTK 2.42.2
It crashed because libGLESv2.so.2 is not installed. This should be impossible since you're using Tech Preview. Guess: could it be https://github.com/flatpak/flatpak/issues/5570 yet again?
Anyway I'm going to reject this one; libGLESv2.so.2 is simply required to be present, so the crash is expected if it's missing.
*** Bug 266874 has been marked as a duplicate of this bug. ***
*** Bug 266875 has been marked as a duplicate of this bug. ***