Extrude Line. Please.

Countless forums and users requesting this feature be brought back as it is a basic feature in every cad program.

Plenty of examples in there why it would be useful and NECESSARY. Any progress on this?
Just want to extrude this arc into a curved surface to split an stl with.
Can I even create a curved plane to split a stl with? is that an option? or like a sheet solid. anything.

Also can I not create a plane normal to my view?
Say I have an abstract STL, and I need to draw a sketch on one face of the object, but i cant select that face because it’s unibody and slightly curved. how do i create a sketch normal to that face?

the only way ive found is to rotate the object so that face is normal to either the x,y, or z planes, so that i can create a sketch on those. Do I need to make a sketch from the top plane, draw a rectangle normal to the face on the object that i want to create sketch on, exit sketch, extrude rectangle, and then create a plane from that rectangle to sketch on, and then i can delete the rectangle? I mean what if I need an Isometric Plane?!? I don’t get it.

Give an example sketch of what you are trying to achieve.

Extrude a rectangle and orient the face to the surface you need to affect. Use that face to create an offset plane. Draw on the plane and use project to the stl?