/usr/share/doc/pybtctool/changelog.Debian.gz is in pybtctool 1.1.42-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/pybtctool/../python-bitcoin/changelog.Debian.gz
/usr/share/doc/pybtctool/../python-bitcoin/changelog.Debian.gz