r.sunhours(1grass) on Linux
The text 1b3e6258a308, as Debian 13 (Trixie) shipped it. The page shows this text now.
Calculates solar elevation, solar azimuth, and sun hours. Solar elevation: the angle between the direction of the geometric center of the sun’s apparent disk and the (idealized) horizon. Solar azimuth: the angle from due north in clockwise direction.