Product review (5 stars): Same thing you get at a local store, only cheaper
It is bad that in 2013 dryers cannot be designed with small magnets (surrounded by plastic or brass to separate them from the surrounding ferric metal) so that physical switches can be done away with. But unfortunately, they aren't, which is where these little things come on. Mine broke due to normal use (I suspect I hung it on some items I was removing from the dryer) and needed a replacement. Local stores wanted up $xx for it, but suppliers on Amazon had it for half that, including shipping. Installation was easy enough, the hardest thing was getting the power connector of the broken switch disconnected due to the locking design, and it worked like a charm.

I don't think it is a Whirlpool supplied part, but simple things like this are usually supplied by third party manufacturers to Whirlpool themselves for economic reasons (cheaper to order a million switches at $1 each than spend $2 million on the machinery, components, labor, and space to make it themselves).