E package-installs-apt-sources

Debian packages should not install files under /etc/apt/sources.list.d/ or install an /etc/apt/sources.list file.

Package sources are under the control of the local administrator and packages should not override local administrator choices.

Packages whose names end in -apt-source or -archive-keyring are permitted to install such files.

Refer to the sources.list(5) manual page for details.