Should the start and end caps return the first and last edge ring even if fill caps is off?

EDIT - I added this as a feature. It seems to make sense.

I think at least some of these selections can be build from existing nodes. I see that you're adding these selection outputs for ease of use and that might be fine. But to judge that, we would have to see how complex it would be to build these selection outputs in a node group.
Also it would be nice if you could describe the reasoning for using the terms "rail" and "profile" edges. Might also be fine, but some justification would be good. Are these terms used somewhere else?

I think at least some of these selections can be build from existing nodes.

When there is only one Source curve or Profile Curve this is true, but once you get multiple, possibly with or without end caps, it gets a lot harder.

I see that you're adding these selection outputs for ease of use and that might be fine. But to judge that, we would have to see how complex it would be to build these selection outputs in a node group.

Maybe someone smarter than I can build groups for this that handle the case above (multiple curves on one or both of the input geometries)

Also it would be nice if you could describe the reasoning for using the terms "rail" and "profile" edges. Might also be fine, but some justification would be good. Are these terms used somewhere else?

'Rail' Edges was my own term, the best I could come up with. Representing the Duplicated edges of the original curve. Where "Profile Edges" is the edges that are the duplicated "Profile Curve" input. I'll note that in the description.

In D15479#433193, @Jacques Lucke (JacquesLucke) wrote:

I think at least some of these selections can be build from existing nodes. I see that you're adding these selection outputs for ease of use and that might be fine. But to judge that, we would have to see how complex it would be to build these selection outputs in a node group.
Also it would be nice if you could describe the reasoning for using the terms "rail" and "profile" edges. Might also be fine, but some justification would be good. Are these terms used somewhere else?

Those output selection would be quite nice to have I think, for UVs and other effects.
A bit like the extrude node.

Maybe is there was a way to expand/hide some part of a node.
So that it could be hide inside a ''selection output''. As to not clutter a node visually. A bit as what was proposed with the new Principled V2

https://devtalk.blender.org/t/principled-v2-feedback-discussion-thread/24997/117?u=fr002

We talked about this recently in the context of panels in nodes (see D16633). If these were in a collapsible subpanel, I think the UI cost for their addition would be much lower. As it is it's just hard to stomach making the node so much taller.