Exhaust cross-over pipe mystery insert

[RuralTowner]

Replacing the exhaust cross-over pipe on my 8BA due to a thumb-sized rot hole in the lower passenger corner. Saw what appears to be a possible factor insert that's not present in the very-good-used replacement off ebay. Looks like it would obstruct >1/2 the exhaust pipe opening unless it was meant to serve some purpose since the driver's side dumps right next to the front passenger.