How do you UV unwrap hair/fibers in Blender?

I’m learning the hair systems in Blender and I was wondering how could I unwrap the final hairs (without hair cards), so that I would texture them in another application?

PS: In other words is there an equivalent to Zbrush’s fibermesh option “FiberUV”?

No way to do that for default particle hair. For new Hair Curves, you can deform some kind of mesh along the curve and use its UV coordinates. Only possible through Geometry Nodes (hair curves are borderline useless without them). I made few node groups for that

Keep in mind that Hair Curves are currently so bugged that you cannot easily convert them to mesh or export to *.FBX, even if you gave them mesh profile using geonodes. It will also need a hack workaround