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