It also applies to the actual Szechuan Peppercorns when ground. Most Szechuan Peppercorns are sold already ground in Japan.
The leaves have a bit of a citrus-fruit aroma, and a milder pepper taste than the berries (aka Szechuan Peppercorns) do.
Sansho means “wild pepper”. It’s derived from one of the Chinese names, “shan jiao”.