Add "This is archived/old content" banner for old documentation pages

Problem/Motivation

Users are finding old Drupal 6/7 doc pages, and they look relevant and updated:
https://www.drupal.org/forum/support/post-installation/2025-06-07/time-z... →

It might be worth considering adding a "This is archived/old content" banner or something, like the warnings that api.drupal.org just got, making it clearer that some of these are old or archived documentation pages. It could be added automatically at the top of all pages under certain paths? See for example, a page like this:

https://www.drupal.org/docs/extending-drupal/contributed-modules/contributed-module-archive/contrib-modules-for-building-the-site-functionality/dates-and-events/datecalendar/drupal-6-datecalendar/date-locale-time-zone

https://www.drupal.org/docs/extending-drupal/contributed-modules/contrib... →

It says:

Date Locale & Time Zone settings

Last updated → on 30 April 2025

[...]

... so a user may easily miss that this doc page is for an older version.
Based on discussion in 📌 Migrate documentation into the new system Active .

Proposed resolution

Could we get a "old docs" warning banner for pages under https://www.drupal.org/docs/extending-drupal/contributed-modules/contrib... → as well, alerting users that this is for an old version, Drupal 6 or 7?

A rule could be, that since it's under https://www.drupal.org/docs/extending-drupal/contributed-modules/contributed-module-archive a message like this could be shown at the top of the page?

We have a notice like that for D7 documentation already. For example: https://www.drupal.org/docs/7/understanding-drupal →

A rule could be, that since it's under https://www.drupal.org/docs/extending-drupal/contributed-modules/contributed-module-archive a message like this could be shown at the top of the page?

Remaining tasks

Decide if we should add a banner warning above old doc pages.