The flow policy family is a special case of a finite-state machine at the family instance level. It allows defining a set of internal states, defining rules for transitioning between these, and managing the current state for each flow family instance.
A declaration of the flow family is in the following file:
/opt/KasperskyOS-StarterKit-<version>/sysroot-x86_64-pc-kos/include/kss/server/flow.cfg