Yes, it's True, the Volume with INDEX (NIFTY and BANKNIFTY SPOT).
Index trade size is the cumulative trade size of constituting symbols
Let's have a look.
Image 1:- MZPACK Orderflow / Footprint with NIFTY SPOT
Image 2:- FIn- Alg with NIFTY SPOT (Orderflow / Footprint)
Image 3:- Fin-Alg (Market Profile TPO)