Constant input_sys::libinput_pointer_axis_source_LIBINPUT_POINTER_AXIS_SOURCE_WHEEL_TILT

pub const libinput_pointer_axis_source_LIBINPUT_POINTER_AXIS_SOURCE_WHEEL_TILT: libinput_pointer_axis_source = 4;

The event is caused by the tilting of a mouse wheel rather than its rotation. This method is commonly used on mice without separate horizontal scroll wheels.