One column of the jumper header
Absolute column position, 1-based from the board's left edge
Top-row pad: role tokens (e.g. [\"sel_c\",\"swclk\"]) or [\"np\"]/[\"nc\"]
[\"sel_c\",\"swclk\"]
[\"np\"]
[\"nc\"]
Bottom-row pad
Optional third-row pad (X pins), present only where one exists
One column of the jumper header