Description of problem:
Epiphany now looks in /usr/lib/epiphany/2.29/ for extensions, but they are installed in /2.30/. As far as I can tell, this is because they should be installed according to "ephy_api_version", not "ephy_major" any more.
Version-Release number of selected component (if applicable):
Indeed, adding a link solved the issue for me.
A rebuild fixed it for me, here is a patch.
Created attachment 412402 [details]
Patch to adapt epiphany-extension to new layout
I've fixed this in the 2.30.1 build of the extensions.
*** Bug 591465 has been marked as a duplicate of this bug. ***