This is the world that CU used for its survival gamemode in Minecraft 1.8 (2014-2015)
In the early days of the CU revival, there was a rather...slow update process. The server began on MC 1.7.10, and this world continued to be used after the update to 1.8 - resulting in some areas of the map where new chunks were generated with the new world generator due to biome changes. It was not until the update to MC 1.10 that this world would at long last be retired in favor of a clean slate.
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.