/usr/share/sgml/entities/xml-iso-entities-8879.1986 is in sgml-data 2.0.10.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/sgml/entities/../../xml/entities/xml-iso-entities-8879.1986
/usr/share/sgml/entities/../../xml/entities/xml-iso-entities-8879.1986