/usr/share/mozilla/extensions/{a463f10c-3994-11da-9945-000d60ca027b}/formhistory@yahoo.com is in xul-ext-form-history-control 1.4.0.6-1.
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/form-history-control