Bug#1067079: Clarify that policy on a technology does not implicitly mandate that technology

[Josh Triplett <josh@joshtriplett.org>]

On Mon, Mar 18, 2024 at 05:38:15PM +0800, Sean Whitton wrote:
> Was there some recent packaging situation that prompted you to think
> about this?  I'm cautious about adding it in the absence of that.

Mostly, recent discussions in various places regarding whether packages
are required to use *cron* to run periodic jobs. Policy says what
packages must do if they install a cronjob, but that itself does not
mandate the use of cron specifically. It seemed worth explicitly stating
the understood-but-unwritten interpretation that having Policy about XYZ
does not mandate that packages use XYZ.

I've also seen a few arguments over the decades that amount to "Policy
talks about A, and doesn't talk about B" being used as some amount of
weight towards A or against B.

And finally, I have occasionally seen someone try to build a Debian
package by sitting down with the Policy manual, and start down the route
of trying to supply everything Policy talks about that seems like it
makes sense for the package. The mention of "Policy talking about where
to install info documentation, but that doesn't mean you have to have
info documentation" was not a hypothetical; I've seen that and similar
reasoning a non-zero number of times.

I figured that something like this text would help address all of those.