A wide drawer is a harder thing to build than a wide door, and the reason is that nobody pulls a drawer from the middle.
People take hold of whichever handle is nearer and pull. On a narrow drawer that hardly matters. On a drawer running the full width of a wardrobe, pulling from one end turns the drawer slightly in its opening - the near side comes out, the far side lags, and the drawer skews across its runners and jams. Push it back and it jams again. Within a year the corners are worn and it never runs sweetly.
Side runners alone cannot prevent it, because they are too close together relative to the drawer's width to resist that twist.
So our master Indian artisans fit a centre runner beneath every wide drawer as well - a guide down the middle of the carcass, with a matching groove in the drawer bottom's rail. The drawer is then constrained at three points instead of two, and a pull from one end cannot rotate it. It comes out straight however you take hold of it.
It is invisible once the drawer is in. You only ever notice its absence.