Hair: Where did TanRot go? (2.48 feature)

I just dug out Blender 2.48 to use the TanRot (Tangent Rotation) feature for fur control. It uses a vertex group and translates it to a rotation of each hair around its rout. Like combing, but controlled through a Vertex group.
There’s a similar feature TanVel (Tangent Velocity).

Where did they go in Blender 2.9? Is there a substitute? I would be happy with any method of hair rotation control, through vertex group or by a texture, but in the textures there is no option for this either.

I need it for export/import, so combing doesn’t work (unless there’s a method for exporting the comb data into a texture?).

I feel so old to use 2.48 now… :frowning:

Is there nothing?