/usr/share/mozilla/extensions/{a463f10c-3994-11da-9945-000d60ca027b}/{e968fc70-8f95-4ab9-9e79-304de2a71ee1} is in xul-ext-useragentswitcher 0.7.3-1.
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/useragentswitcher