You're reading the documentation for an older, but still supported version (GL013300).
For information on the latest version, please have a look at GL013301.

SPLINE_VELOCITY_OPTION

This is an enumeration type constant that refers to velocity control option of each waypoint when spline motion is controlled in the robot controller, and is defined as follows.

Rank	Constant Name	Description
0	SPLINE_VELOCITY_OPTION_DEFAULT	Variable velocity motion
1	SPLINE_VELOCITY_OPTION_CONST	Constant velocity motion

Defined in: DRFC.h

typedef enum {
    SPLINE_VELOCITY_OPTION_DEFAULT,
    SPLINE_VELOCITY_OPTION_CONST,
} SPLINE_VELOCITY_OPTION;