SVG spec--lines

Hi.  I'm confused by a couple of parts of the SVG spec.

The 'line' element spec says:
"Because 'line' elements are single lines and thus are geometrically
one-dimensional, they have no interior; thus, 'line' elements are never
filled (see the 'fill' property)."

But the 'fill' property says:
"The zero-width geometric outline of a shape is included in the area to be
painted."

This would give a definition to 'fill' for a line.

Are these statements contradictory?  If so, which is correct?

There does seem to be a fill in the Adobe viewer, because there is a line
down the middle of my line when I make my line dashed and wide.

<svg width="592" height="473" viewBox="0 0 592 473">
<g>
<line stroke="#ff0000" x1="50" y1="200" x2="500" y2="200"
stroke-dasharray="20 10" />
</g>
</svg>

That line goes away when I set 'fill' to "none".

Thanks for comments,
andy