This is the Survival world that CU used from 1.15.2 until 1.16.1. Due to issues with 1.13 chunk generation, the world was "soft-reset" during its lifespan. This is the version of the world that was used after that reset. The reset took place on April 4, 2020. You can read more about the reset 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.