That's the front of the boot and the tongue in particular. Look at the top of the black portion--the tongue--there is a cloverleaf there that is also part of the tongue. And of course, it's all sewn by hand, probably with silk thread using a small, fine hair for a "needle." I would wager that it is sewn at 30 spi at the minimum. Why is it famous? Because one of the Elder Shoe Gods--Devlin or Rees or maybe even Leno--mentions it in the early literature. I don't know if this particular boot and this particular cloverleaf tongue is the one mentioned but it was exemplary of fine work, as I understand it.