Epiiphany extensions licenses

[Ivaylo Valkov <ivaylo e-valkov org>]

Hello, list

After few days I am going to release small Epiphany extension written in
JavaScript  with Seed. It turns on and off the JavaScript engine from a
statusbar icon.

What confuses me are the license requirements for Epiphany extensions.
There is a COPYING.README file in the official extensions package, that
states that a special exception notice needs to be added, allowing
linking with Mozilla's XPCOM library. Is this still valid, since the
migration to the WebKit engine?

I am planing to release the extension under the terms of the GNU GPLv3
(or later). I am not obligated to use the GPLv2 (or later), because that
is the exact license notice of Epiphany, right?