Any citizen of the megacity can be classified as a civilian, but there exists a model of android designed for the specific purpose of being one.
The Urbanite Thinkbots are marketed as the ultimate city-dwellers - a standardized android model capable of performing tasks at a low wage to no complaint. These thinkbots require little in the way of amenities, and are satisfied with living in the small communal dwellings they are assigned to. Thus, the perfect civilian.
There was a time where humans would argue that the urbanite thinkbot series deserved higher quality living, but when it came down to it, not a single model felt unsatisfied with their current situation. The situation, while unresolved, has rarely been brought up since.
That said, these civilian androids are not without their own opinions. Many are programmed with desires, thoughts and wants completely unique to their brothers and sisters, and continue to change, evolve and adapt over time to the changing surroundings.
Still, they remain as diligent as ever in their mundanity, seeking only to live as they were created - as inhabitants of the ever-growing city.