http://breezewiki.vernccvbvyi5qhfzyqengccj7lkove6bjot2xhh5kajhwvidqafczrad.onion/minecraft/wiki/The_End
The first ring ends at ±370,719 on the X and Z axes, cutting off terrain generation in a doughnut shape. It continues empty, but the second ring starts at X/Z=(-)524,288, then disappears again at X/Z=(-)642,111 and comes back at X/Z=(-)741,456.