JAR and FAR regulations require the manufacturer of an airliner to demonstrate TO and Landing with a crosswind component of 0.2x Vstall, except that he must demonstrate 20 knots however low his stall speed is but doesn't have to demonstrate more than 25 knots however high it is. They usually try to demonstrate as much as they can find, but run out of time while trying to get the a/c certificated. They may give a number for their simulator experience, but that's only as good as the simulator, which may not be based on valid data in ground effect etc.