https://www.google.com/search?q=coas...GVRDA4XU5kJ5M:
"A clutch mechanism allows the hub to engage and drive the bike forward. The clutch then disengages for coasting or
braking. Rotating the pedals backwards expands the
brake shoes into the steel hub in order to slow the bike. ... When the pedals stop turning, the clutch pulls away from the hub shell."