/usr/share/mozilla/extensions/{86c18b42-e466-45a9-ae7a-9b95ba6f5640}/{fbfbf0bf-032e-427e-932d-0b000a34f168} is in mozilla-biofox 1.6-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/mozilla/extensions/{86c18b42-e466-45a9-ae7a-9b95ba6f5640}/../../../xul-ext/mozilla-biofox