Scores represent all kinds of numerically quantifiable values for a city. They are used for displaying statistics to the player and checking win conditions.
The different Score Scripts each implement a way of calculating a score value. They are available as ScriptableObjects in the CityBuilder/Scores Context Menu.

You can easily create your own scores by inheriting from Score and implementing the Calculate Method.

Some of the Scores included in CCBK are:

Average Building Score

Calculates the average value from different values assigned to Buildings

Tent:0 Hut:50 Palace:100 > 1xTent 2xHut 2xPalace = 60 Housing Quality

Average Service/Risk Score

Averages out the risk/service value of a defined building category

how well are housings supplied with water, whats the general risk of collapse across my city, …

Building, Item, Population Score

Just counts the number of a building that exist.

how many pyramids have been built, how many diamonds stored, how many plebs live in town, …

Coverage Score

Calculates the number of people buildings would cover against the current population count

1 temple covers 1x100 , 2 shrines cover 2x50 > population=400 => 50% Coverage

Multiplied, Summed, Threshold Score

can be used to transform other scores

culture = entertainment + monuments, different threshold of employment, …