When a page is rendered from various sources, such as:

• the page itself,
• local images,
• foreign repository images,
• transcluded templates,
• other pages transcluded,
• pages transcluded from other wikis,
• transcluded special pages,
• etc.

we currently only can address a specific version for the page source.
For anything else, the current version at the time of page rendering
is taken, but we do not send their actual version information anywhere.

The latter should be changed. We do show templates already at edit
pages in preview, a similar list could be included in rendered pages
metadata or comments, along with an "oldid". This would make saved
renderd content more valuable because with the version information,
possible conflicts, errors or bugs were easier to trace and could be
attributed to specific versions.

If I am right with the assumption that the youngest oldid in a list
would sufficiently determine all others, we had a pretty simple way
to refer to historic versions of pages as they appeared to a certain
point in time. Otherwise, all oldids were necessary but still, knowing
them would allow us to refer to historic pages as they once were
without having to accept newer versions of templates or images.
We could even mix - render a page from history, but with a broken
image fixed, and so on.

At least being able to show previous versions of pages as they really
were at their time is imho a goal of quite some value, and will likely
be asked for increasingly often as Wikis become more pervalent in ones
everydays life.

Version: unspecified
Severity: enhancement