This feature has been deprecated. You may be looking for Rift Chunks (1.16)
Rift Chunks are a unique type of chunk that can generate in any dimension.
Rifts greatly increase the refueling rate of the TARDIS, as well a cutting the time to grow one in half.
When generating chunks, there is a one in ten chance that any chunk will be a rift.
A Rift chunk has no physical appearance. Currently, it can be identified by one of two methods: