/usr/share/doc/gambas3-gb-qt4-ext/changelog.Debian.gz is in gambas3-gb-qt4-ext 3.8.4-2ubuntu3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/gambas3-gb-qt4-ext/../gambas3-runtime/changelog.Debian.gz