Correct me if I'm wrong, but unattended-upgrades is meant to automatically install security upgrades. It's suitable for Debian stable, which have a security suite (debian-security), from where security upgrades are available.

Kali is a rolling distro, there's not security repo, there's only the kali-rolling suite. So unattended-upgrades is not for Kali. What did you want to achieve with unattended-upgrades?

No. Unattented-upgrades are to keep updated all packages via APT, even for security reason or for improve reasons. It make automatically same thing than using manually apt-get upgrade or apt-get full-upgrade.

It's not because Kali is a "Security distro" that you don't need to keep it up to date ;) And always take a look manually for updates is not very useful in many situations.

Anyway, I just inform the precompiled package with 50unattented-upgrades file doesn't fit what expected to work as-is for Kali on Kali, it seem to be ported from Debian directly without adjusting parameters.

It's not because Kali is a "Security distro" that you don't need to keep it up to date

It's not about keeping the system up-to-date yes/no, it's about doing so unattended. The primary use-case for unattended-upgrades is a stable distribution, most likely running on a server. This is because a stable release only receives targeted updates, either security fixes, or bug fixes for bugs that were considered important enough to be fixed. In this context, it's safe enough to upgrade the system automatically, without human validation: it's unlikely to break things, and in any case, the upside of applying security fixes asap outweighs the risk of breaking something.

Now, a rolling distro? For a rolling distro I strongly advise NOT to update it with unattended upgrades, sooner or later it might break your system. For a rolling distro, I'd recommend attending uprades: user decide to upgrade, check the output of apt, and hit Enters only if everything looks good.

Now, of course you do what you want with your system, and if unattended-upgrades works great for you and your Kali install, all the best.

Anyway, I just inform the precompiled package with 50unattented-upgrades file doesn't fit what expected to work as-is for Kali on Kali, it seem to be ported from Debian directly without adjusting parameters.

Yep indeed, the package comes from Debian unmodified. If you get it to work for Kali, please share your config here, and I'll include it in Kali so that other users can benefit.

Like I already wrote:

Basically the default current configuration in 50unattended-upgrades file under Origin-Pattern should be something like that:

Unattended-Upgrade::Origins-Pattern {
"origin=Debian,codename=${distro_codename},label=Debian";
"origin=Debian,codename=${distro_codename},label=Debian-Security";
"origin=Debian,codename=${distro_codename}-security,label=Debian-Security";
};

The manual solution I found for the moment is to edit the file to put in comment or remove all lines containing "origin=Debian,... or o=Debian,...", then and add this:

Unattended-Upgrade::Origins-Pattern {
"origin=Kali,codename=${distro_codename}";
};

To keep updated all packages provided from Kali repositories.