The rules that use the category "<unit-sing>" are:

<engage_command>

take <unit-sing> with <armament>

<guide_ship>

<unit-sing>

<engage_command-not_added_salvo>

take <unit-sing> with <armament>

<guide_command>

<unit-sing> designated guide

designated guide is <unit-sing>

guide on <unit-sing>

<basic_nl_command>

<unit-sing> <commander_phrase> <unit_command>

<unit-sing> <unit_command>

<zoomable_thing>

<unit-sing>