This is the Survival world that CU had from 1.13 until the soft reset that took place in 1.15.2. Due to server crashes of increasing frequency that were all related to chunk I/O with this world, we opted to do a soft reset of survival where any users who requested that their build be copied over would be manually transferred. The new world uses the same seed and has identical terrain to make copying/pasting people's builds easier. The reset took place on April 4, 2020. For more details on the reset, check the related announcement here:
You cannot take this map, or any structures within it, and run it in your own server or someone else's. This is only for those who wants to continue their projects on it instead of having to start over in single player mode. Breaking this rule will result in your download privileges being permanently suspended and could result in your account being banned.