Yeah, I'm curious about that as well, I just updated my minecraft and went to my quarry and saw shape in the bedrock and when got closer, it identified as Fractured Bedrock. I believe it wasn't there before.
Think Factorization is going through alot of changes this version, so Neptune has been adding things to world gen before completing functionality. One example is the giant robot things at "the end of the world" as he puts it I think, the robots wake up and everything but just seem to do a debug dance thing(look it up, it is pretty cool and funny)
Well, if that the case, it's not that helpful, since you probably has already removed all the blocks when you see the fracture bedrock. Like getting a sign about a hole in the ground, after you already fallen into it. I was actually kinda scared about it, thinking "If I break this, it might break into a vacuum and stuck me into the void!"