Dear Maintainer, See the command and the output: ------- debian@trixie:~$ LANG=C apt-get source -t FOO linux-base Reading package lists... Done E: The value 'FOO' is invalid for APT::Default-Release as such a release is not available in the sources E: Unable to find a source package for debian@trixie:~$ ------- I expected: "E: Unable to find a source package for linux-base"