R-15 insulation has been placed below the basement floor slab, over a continuous vapor barrier. Radiant heat tubing is to be placed next and then concrete will pour.
The 2015 International Residential Code requires R-10 insulation below slabs in our climate zone. We're going for 150% of insulation requirements in all envelope assemblies. A PassiveHouse, in contrast, would probably have R-40 or greater below the floor slab.