Layer Estimates:

Layer: LayerB_polygon (ID:0)
Count: 15
Extent:

XMin: -8380942.3702
YMin: 326979.878199998
XMax: -8380718.41554022
YMax: 327132.738299999
Spatial Reference: 102100 (3857)

Layer: TableB_child (ID:2)
Count: 11

Layer: TableB_grand_child (ID:3)
Count: 6