Repo: "deb http://deb.theforeman.org/ buster 3.3"
Key: "https://deb.theforeman.org/pubkey.gpg"

Registration will fail with:

E: Type 'deb\' is not known on line 1 in source list /etc/apt/sources.list.d/foreman_registration.list
E: The list of sources could not be read.
E: Type 'deb\' is not known on line 1 in source list /etc/apt/sources.list.d/foreman_registration.list
E: The list of sources could not be read.
E: gnupg, gnupg2 and gnupg1 do not seem to be installed, but one of them is required for this operation
(23) Failed writing body
E: Type 'deb\' is not known on line 1 in source list /etc/apt/sources.list.d/foreman_registration.list
E: The list of sources could not be read.