/usr/share/mozilla/extensions/{a463f10c-3994-11da-9945-000d60ca027b}/{8f8fe09b-0bd3-4470-bc1b-8cad42b8203a} is in xul-ext-livehttpheaders 0.17-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/mozilla/extensions/{a463f10c-3994-11da-9945-000d60ca027b}/../../../xul-ext/livehttpheaders