They are almost always even splits, with a consistent pace through the entire race, though this can be adjusted if the runners request it; that is rare though.
They typically have green lights, which is the target pace, and then a set of blue lights ahead of them, which gives a visual indicator of how far ahead a runner is from the green lights.
[Josh Kerr's coach, Danny] Mackey was set to have a meeting with representatives from Wavelight on Tuesday to discuss the pace. He said they have yet to lock in specific splits, but Kerr told LetsRun.com in April that “an even split or a slightly negative split, I think, is the way to do it.”
3:43.13 mile pace is 55.45 per 400, which would mean 1:50.90 at 800 if they were to go for even splits.
Mackey says he hopes the pace is pretty even and “hopefully he’s got something left in the end.”
They went through 800m in 1:51.1 according to another comment in this post.I would guess it's just uniform world record pace, and it's up to the runner to use their own strategy - stay just in touch with the light for the first three laps and overtake it on the fourth, or something.