The variable name matched the RSS tag it ended up in, but was misleading
about what it actually was—because if you actually want “last build
date”, you should use `now()`. (Due to the potential for edits, I think
that either there should be an official `updated` field on pages, or
that these templates should use `now()`.)
Two main purposes of changes here:
- To make the formatting and indentation of the raw output prettier;
- To simplify the HTML yielded by dropping unnecessary bits.
The 404 changes are a tad more extensive, altering the actual wording to
match conventional stub 404 pages a little more.