Rotate Label adds 90° to the label angle of the selected boards and redraws the label. It does not rotate the board geometry and it does not rotate drill holes. The tooltip and status say: rotate the label 90° on the selected board(s) and redraw it.
The board must already have a label: the board-index attribute written by ABF Extra Label. Otherwise a message says to select a labelled board (run ABF Extra Label first). Several boards are rotated together in one undo step named Rotate Label.
The turn is counter-clockwise around the labelled face's normal:
The board is made unique before the redraw, so the label on another copy is not overwritten. Nesting reads this angle when it packs the board. There is no field for an angle other than steps of 90°.
On failure a message reads «Rotate Label error» plus the detail. There is no VCB and no Tab, Ctrl, Shift, or Esc inside the command — it runs once and finishes.