Sparky must be in a hurry
This question appears often, and is asked quite frequently in the field. I have heard of inspectors not allowing cable assemblies identified as URD, for the reasons you state. The inability to locate any approval in publications, is the general reason.
URD, or underground residential distribution cable, can be USE, underground service entrance cable. When it is service entrance cable it is commonly, 3 conductors of Aluminum XHHW, with one conductor identified.
URD identified distribution cable can be medium voltage cable, in the range of 4.16 KV, to 34.5 KV. Of course this will not be marked as USE.