The rules that use the category "<path_prep>" are:

<mine_detection_command>

<mine_detection_command-not_located> <path_prep> <line_loc>

<move_mod-not_compass_direction>

<path_prep> <line_loc>

<assault_command>

<assault_command> <path_prep> <line_loc>

<breach_mod>

<path_prep> <line_loc>