pub fn content_modified(directories: &[&str]) -> Option<DateTime<Utc>>Expand description
The newest modification time across everything that determines page output.
Returns None when the result is implausible, in which case the caller
should omit <lastmod> rather than assert something a crawler can falsify.
Reproducible builds normalise timestamps to the epoch, and a skewed clock
can produce a future date; both are worse than saying nothing.