/usr/share/doc/libfcitx-config4/changelog.Debian.gz is in libfcitx-config4 1:4.2.9.1-1ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libfcitx-config4/../libfcitx-utils0/changelog.Debian.gz