Debian Wheezy ELTS and unattended-upgrades

Debian Wheezy (LTS) reached end of life in May 2018, but fortunately the company Freexian offers with extended LTS (ELTS) a further extension of the lifetime of Debian releases by at least 1 year. After adding the ELTS repositories to APT, it can be set up as follows for unattended-upgrades:

/etc/apt/apt.conf.d/50unattended-upgrades

Unattended-Upgrade::Allowed-Origins {
// ...
"Freexian wheezy-lts";
}

References:
https://wiki.debian.org/LTS/Extended
https://deb.freexian.com/extended-lts/
https://wiki.debian.org/UnattendedUpgrades