Why do some data entries list sources which don even mention the craft/troop/etc.?
The source contained a relevant picture of the craft/troop/etc. An example of this is the Beta-class Assault Shuttle and Gamma-class Light Personnel Carrier. By their descriptions they share a similar appearance to the Gamma-class Assault Shuttle. OR those other sources are connected by an event or character which allows for dating when the craft, troop, etc. existed.