Citizen

The term Citizen designates any human living under the Combine rule in a "City" of Earth, as opposed to a Refugee, who defected from the Combine rule to join the Resistance. The status was established after the Seven Hour War and the subsequent Combine occupation.

Gasmasked Citizen
The Gas Mask Citizen is the oldest known revision of Half Life 2's citizen model. It is a person fully clad in a rubber suit with a brown apron, with his face behind a gasmask. According to Marc Laidlaw, it was cut so Valve could focus more on their facial animation system.

The model in the Leak (believed to be "Citizen.mdl", referenced in many early WC maps) is long gone (with a few potential descendants still present), and all that remains of it are its textures.

It's symbolic of the earliest eras of Half-Life 2's development, while the atmosphere still was toxic enough to necessitate gasmasks.

Sitting Factory Worker
The "citizen/factory_sitting" folder contains textures for an unused Citizen. This one appears to be wearing a blue outfit with City 17's logo on his back. He uses a full-sized version of the face used on the Cheaple Citizen model in the final game. Based on the name of his texture folder, this Citizen would be sitting on a chair with a desk in front of him in the factories, an area removed from the final game. There would also be a piece of paper somewhere.

The model for this character is missing. The face texture for this NPC is a high-resolution version of the one used in the final's "cheaple" citizen model.

The overall shape of the Sitting Worker's texture is the same as the one used for Mossman's old body textures, suggesting the same artist worked on both of them.