DEB822-STYLE format for Ubuntu 24.04+ apt repository instructions (.sources)

Ubuntu from 24.04 is now migrating to defaulting to the use of DEB822-STYLE sources.list.d format files, in particularly when you use add-apt-repository. There should be instructions of creating a /etc/apt/sources.list.d/nvidia-container-toolkit.sources file in the https://docs.nvidia.com/datacenter/cloud-native/container-toolkit/latest/install-guide.html website.

My current sources file looks like below, but it's also possible to embed the GPG key into the file as well, the key needs to be indented by one space below Signed-By.

Enabled: yes
Types: deb
URIs: https://nvidia.github.io/libnvidia-container/
Suites: stable
Components: main
Architectures: amd64
Signed-By: /etc/apt/keyrings/nvidia-container-toolkit-keyring.gpg

Or

Enabled: yes
Types: deb
URIs: https://nvidia.github.io/libnvidia-container/
Suites: stable
Components: main
Architectures: amd64
Signed-By: -----BEGIN PGP PUBLIC KEY BLOCK-----
 .
 ${ GPG KEY CONTENTS }
 -----END PGP PUBLIC KEY BLOCK-----

My source file looks like the above, however, I am receiving an error Error: The repository 'https://nvidia.github.io/libnvidia-container stable Release' does not have a Release file. . I'm currently on Ubuntu 24.10, but this method was previously working for me on Ubuntu 24.04. Either way, having some instructions for the new source file format would be beneficial. I'll see in the meantime if I can resolve my error.

Start by reviewing the NVIDIA Container Toolkit install guide and the linked Ubuntu DEB822-STYLE sources documentation. Check the reported .sources examples and the Ubuntu 24.04+ repository behavior, including the Release-file error on Ubuntu 24.10. Done means the install guide clearly documents the supported source-file format and key configuration options.