Field 28, worldTime, holds the world time of a link made away from live:
zigzag seconds since 2026-01-01, like field 8, but it may lie ahead of the
link's creation (a forecast moment). Opening such a link pauses the world
clock at that time; a link without it leaves the clock alone, so a page
opens live and Back or Forward does not stop a replay. Times no JS Date
can hold are dropped.