Yesterday morning only two kittens were in the box. We didn't see hide nor hair of the mamma. Miss M set out a bowl of cat food topped with a spoonful of tuna. We checked on them periodically throughout the day and gave them a dropper full of water later in the evening.
We were prepared to go into full-on kit* rescue mode this morning if necessary. Zero kits this morning but the food bowl was empty.
There have since been two sightings of mamma in or near the garage. AND the food bowl is again empty.
So... . The kits are around here somewhere and Miss M is doing her best to see that the mamma is well-fed.
*"Kits" because the mamma can apparently read. She put them in the old packing box marked "kit."