/usr/share/doc/libhttp-parser2.1-dbg/changelog.Debian.gz is in libhttp-parser2.1-dbg 2.1-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libhttp-parser2.1-dbg/../libhttp-parser2.1/changelog.Debian.gz