Valve seat and gasket for exhaust bypass valve

An assembly can include a valve seat for an exhaust bypass valve of a serial turbocharger system; and a gasket that includes a planar portion that defines a perimeter and that includes a tab that extends from the perimeter of the planar portion for engagement with the valve seat to secure the gasket to the valve seat. Various other examples of devices, assemblies, systems, methods, etc., are also disclosed.