/usr/share/doc/lilypond-doc-html-zh/changelog.Debian.gz is in lilypond-doc-html-zh 2.18.2-4.1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/lilypond-doc-html-zh/../lilypond-doc-html/changelog.Debian.gz