Feathering and the "marching ants"

When I make a selection, I see the "marching ants" where the selection is. If I grow/shrink the selection, I see the "marching ants" where the selection ends up.

When I choose to Feather, it looks like the "marching ants" do not display the correct placement of the selection. For example, I start with this round selection on a tag :

If I add a Feather to that selection, the "marching ants" show a smaller selection:

That gives the impression that the selection is smaller than the original. However, if I fill that selection, it shows that the color extend the "marching ants" so I am getting an inaccurate representation of how much feathering I would actually need to achieve the result I want.

Is that the normal and expected behavior on how the Feathering is displayed?

To me, it looks completely opposite of what I would expect. In this format, I have no clue how much feathering I would need to stay within the dimensions of the tag, for example.

I am using V3.0.3 on Windows 10 if it makes any difference.

Quote from Old Bruce

I think that the marching ants show the point where the opacity (feathering) is at 50%, not the extreme outer bounds which would be a fraction of 1%, nor at the minimum where the opacity would be at 100%. I could be wrong about the cut off being 50% opacity.

Maybe so, but is there a way to know how far the selection is? It does not make sense to have only a partial "image" of the selection area.

Is there another way to get that?