The rules that use the vocabulary item "where" are:

<np-gapsout_null-gapsin_null-wh>

where

<controller_flight_advisory>

where are you

<zoom_operation-gapsout_null-gapsin_null>

where is <zoomable_thing-gapsout_null-gapsin_null>

<np-gapsout_null-gapsin_null-wh-sing>

where

<np-gapsout_null-gapsin_null-wh-pl>

where