I have version 475.01 and I have no extra unhappiness
EDIT: Also I have never seen very unhappy citizens
I think 474.
x is floppy, and 475.
x is CD. 475.01 would be the original version but for CD.
Here is a look at redshirts on 474.04.
My best-guess explanation of this screenshot is based on very old posts by Valen and Urtica Diotica.
A base integer is derived from difficulty setting:
Chieftain 14
Warlord 12
Prince 10
King 8
Emperor 6
A multiplier from Government:
An/Des ×1
Mon/Com ×1.5
Rep/Dem ×2
The result is the number of cities that can be in the empire before you begin to get additional blackshirts. On Emp+Dem (pictured), this is
12. When a 13th city is founded, apparently a new blackshirt appears in just the 6th city on the roster, and as well as in the other increments of
12 from the 6th city, once those cities are built. And when the 14th city is founded, a blackshirt is then applied to the 7th city. This keeps going and wraps around. Every new city is basically adding a new blackshirt to every twelfth city.
When you run out of born-contents, it doesn't stop; instead the redshirts appear. A city with 0 born-contents has all blackshirts, but a city with a negative born-content has a redshirt in there as well.
Nottingham (pictured) got 2 blackshirts from somewhere between the 13th and 25th city, and the likewise 37th. It then got redshirts from the 49th, 61st, 73rd, 85th, 97th, and 109th cities on the roster, or something like that.
Redshirts have some aberrant behavior that can be advantageous. It should cost 4 diamonds to make it content or 6 to make it happy, but a deduction from the city screen suggests that it only costs 2 diamonds to turn a redshirt into a happy. The city produces 15 diamonds: evidently 12 are used to turn 6 redshirts happy, and the last 2 are used to turn 1 blackshirt into a content. On the other hand redshirts still count double when the temple, cathedral, colosseum, and Bach are used to pacify them.