[samueloph]

> Debian Jessie is terribly out of date and hasn't seen regular security updates for five years now, from https://www.debian.org/releases/jessie/:

Nowadays you get 10 years of support if you make use of the Freexian project.

Even the page you linked mentions that:

> Jessie also had benefited from Long Term Support (LTS) until the end of June 2020.

And then you can use the ELTS support, which goes up until 2025: https://wiki.debian.org/LTS/Extended

So yes, users should not be running such old releases, but there's still support. And even though Freeexian's support is not officially affiliated with Debian, it's done by Debian Developers.

If you want to run this SteamOS release, you should consider pointing to Freexian's repo for security updates.