I didn't think this one a lot the the others, but oh well.
it's pretty much an arcade gate, but there is no gate map and the depths are randomly chosen (if applicable*).
I think it should start on T2, maybe on Moorcroft Manor's railway. also a T3 entrance in the lower left of emberlight would do since it's almost empty right now. it should scale rewards and everything forever (always if applicable**) and the depths below 29 should be swarm depths. no, you shouldn't reach the core.
I think that the exploration factor that this will provide will get quite a bit of attention. you don't know what you will find down there, so it's actually exploration.
if you want to limit it up, make random heaven gates pop out instead of normal gates. always a chance, and not absurdly high, thanks. also after a while, let's say swarm depths, just make monsters not drop items and replace heart boxes with red boxes. actually, replace all treasure boxes with red boxes, so they don't drop items.
now, the name. random is not that good. unknown is already used for unknown passage and maybe it's better reserved for the 29+ depths. unexplored gates are recon squad work, probably. so, help me out please.

* if full randomization is not applicable, maximum number of gates with no theme will do. if that isn't possible, then no stratum classification, just single depth.
**if looping forever isn't possible, then it should be around 65000 gates. yeah. you should be able to do that. or maybe 1337 or 9001. or 9002, that would be hilarious.