This entity is defined by a single point.

If a workplane is active when the datum point is created, then that point will always lie in the workplane. If no workplane is active, then the point will be free in 3D. This is the same behaviour as for all points, including e.g. the endpoints of a line segment.

Points are typically used as construction geometry. The user might place datum points in order to simplify the dimensioning of line segments or other entities.