Hello, I'm very tempted to mark this bug as "wontfix" and close it.
I agree that in a perfect world, this kind of rule would be backed by some formal documentation like the Debian Policy.
In practice, I think it would be very problematic to have packages in the Debian archive add apt preference files.
As such, if you feel this is important enough, I would encourage you to raise this issue with the Policy maintainers and the Apt team. FWIW, I did ping the later on IRC.
PS: I searched a bit, and this tag was implemented [1] after someone asked for it in #786533.
[1]: https://salsa.debian.org/lintian/lintian/-/commit/f2af87c056f4ed030b5250e572ec3caf58ac8068
-- ⢀⣴⠾⠻⢶⣦⠀ ⣾⠁⢠⠒⠀⣿⡁ Louis-Philippe Véronneau ⢿⡄⠘⠷⠚⠋ po...@debian.org / veronneau.org ⠈⠳⣄
