It looks like sancho is the berry produced by the tree. The leaves look similar to our toothache tree or Hercules Club as some call it. I know that the bark here in NAmerica has been used as a local anesthetic for a long time. It produces a tingly, numbing sensation when it becomes wet. I have used the bark to numb gums or throat pain. I never tried the berries.

My tree here died in the last drought. It was a birdshit variety since it was growing along the fence. The seed was dropped by a bird as it rested on the fence and I got a tree as a result! Gotta wait for the next one I guess.

In the US it's known as "Szechuan peppercorn". Preparing it for use requires carefully inspecting a handful for stems and thorns (which can be quite big), pan toasting and crushing/grinding to a coarse powder.

As pointed out in the sister comment, the spice has a mild numbing effect which counters the heat of chilis. Adding a little to hot dishes makes the flavor more complex and enjoyable.

For people who like to cook it's an ingredient worth experimenting with across culinary boundaries.