The minor yard lines are the yard lines in between all of the major yard lines. Typically, there are four sets of minor yard lines: one near each sideline, and two near the middle of the field
football_minor_yard_line(yard_line_height = 0, feature_thickness = 0)
A data frame of the bounding box of a minor yard line
The height (in the y-direction) of each yard line
The thickness of each minor yard line