DESCRIPTION
In the beta update of next month, the purple fillet gizmo for polygons can be also applied to 2D/3D polylines. This feature will make it easier to create objects like pipes.
When the constraint is U (uniform), the changes of size and radius on one control point will be applied to all control points.
You can also adjust the fillet radius precisely by values in Gizmo->Spline Profile->R.