/usr/share/doc/python3-sphinx-rtd-theme/changelog.Debian.gz is in python3-sphinx-rtd-theme 0.2.4-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/python3-sphinx-rtd-theme/../sphinx-rtd-theme-common/changelog.Debian.gz