Using the anti_tax_rebels which are called peasant rebels in game.
The top section details the traits that the rebels have.
The rebel type which has the highest calculated modifier in this section is the type to spawn (unless a specific type is funded via a spy mission). The spawn chance has various factors which affect it, for example collecting War taxes increases the modifier for peasant rebels by a factor of 2.
This section used the same mechanics as above but instead calculates the provinces that the rebels move into after completing a siege.
The scopes are the last section for the rebels and this details the effects they can have on provinces or countries. This section also details the rebel demands and negotiations possible.