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

<vector>

<vector_prefix> <air_location>

<vector_prefix> <vector_spec>

<vector_prefix> <vector_spec> <vector_purpose>

<vector-has_destination-recursive>

<vector_prefix> <air_location>

<air_locate_point>

<vector_prefix> <air_location-stationary> for <point_name>

<vector-not_has_destination>

<vector_prefix> <vector_spec>

<vector_prefix> <vector_spec> <vector_purpose>