DEB822 was available from at least Buster [0]. I think Bullseye was the first release I used it in. [0]: https://manpages.debian.org/buster/apt/sources.list.5.

DEB822 was available from at least Buster [0]. I think Bullseye was the first release I used it in. [0]: https://manpages.debian.org/buster/apt/sources.list.5.en.html https://manpages.debian.org/buster/apt/sources.list.5.en.htm...