I hate the Aptfile format after looking at it.

The ppa directive hints that this is intended for Ubuntu because otherwise installing PPAs is a great way to break a non Ubuntu distro.

The deb directive uses the old and soon to be deprecated .list file extension. DEB822 format is the replacement.

The key directive adds the key as globally trusted for all repos instead of locking it to a specific repo as recommended by Debian. I think this is required under the new DEB822 repo format.