/usr/share/mozilla/extensions/{3550f703-e582-4d05-9a08-453d09bdfdc6}/gnome-keyring-integration@sebastianwick.net is in xul-ext-gnome-keyring 0.10-1~deb8u1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/mozilla/extensions/{3550f703-e582-4d05-9a08-453d09bdfdc6}/../../../xul-ext/gnome-keyring