Value: true or false (if missing it is false by default)
True means a unit does not participate in combat.
<option name="isInfrastructure" value="true"/>
True also sets, to default, that the unit will be captured if an attacker is successful.
Can optionaly be combined with:"destroyedWhenCapturedFrom", "destroyedWhenCapturedBy", or "whenCapturedChangesInto" to change this.