/usr/share/doc/libpixman-1-0-dbg/changelog.Debian.gz is in libpixman-1-0-dbg 0.24.4-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libpixman-1-0-dbg/../libpixman-1-0/changelog.Debian.gz