This is from Panthera, the cubs (one litter of two and a second litter of one) are in partially manmade dens in Mongolia, whatever that means. (The cats are one hundred percent wild however).
I imagine they created cave-type sites with boulders etc that were accessible to the Researchers and then hoped Snow Leopards would use them as maternity dens, which they did in at least these two cases.
The mother cat can obviously hear the camera moving about as she is looking up at it.