Debian and derivatives have a new *.sources file based on deb822 format to set up system-wide packages repositories.
Ubuntu uses already it since 24.04 release.
This format will replace the sources.list format in the future.

I added the next release (2.19) in version_added but, of course, it should be changed if it will be release in another release. I can remove it too if a maintainer wants to manage it.

closes: #2747