AFAICT the question from comment #4 is unrelated to the current report (can we close it BTW? - basic SVG shapes like for example <line> elements in Inkscape in general are only supported for rendering - Inkscape does not create such elements, nor can they be node-edited without converting to path first - this is tracked in older reports already) about the nodes of the stroke caps when converting stroke to path (the <line> elements use square caps for the stroke, which result in an "extra" node in the outlined stroke where the outlined cap joins the outline line segment itself).
AFAICT the question from comment #4 is unrelated to the current report (can we close it BTW? - basic SVG shapes like for example <line> elements in Inkscape in general are only supported for rendering - Inkscape does not create such elements, nor can they be node-edited without converting to path first - this is tracked in older reports already) about the nodes of the stroke caps when converting stroke to path (the <line> elements use square caps for the stroke, which result in an "extra" node in the outlined stroke where the outlined cap joins the outline line segment itself).