/usr/share/doc/libphonon4qt5experimental4/changelog.Debian.gz is in libphonon4qt5experimental4 4:4.10.0-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libphonon4qt5experimental4/../libphonon4qt5-4/changelog.Debian.gz