tour_distribute_control

tour_distribute_control = {
	scope:activity = {
		add_activity_log_entry = {
			key = increased_control_log
			tags = { good }
			character = scope:visiting_liege
			target = scope:stop_host_scope
			show_in_conclusion = yes
			if = {
				limit = {
					$CAPITAL$ > 0
					NOR = { # Do not apply if CAPITAL and HELD_COUNTIES are the same
						$CAPITAL$ = $HELD_COUNTIES$
						$CAPITAL$ = $HELD_AND_VASSAL_COUNTIES$
					}
				}
				root.location.county = { change_county_control = $CAPITAL$ }
			}
			if = { # County titles held by your vassal and their vassals
				limit = {
					$HELD_AND_VASSAL_COUNTIES$ > 0
				}
				if = {
					limit = {
						$CAPITAL$ = $HELD_AND_VASSAL_COUNTIES$ # Apply to capital if the values are the same
					}
					root.location.county.holder = {
						every_sub_realm_county = {
							custom = every_title_held_by_vassal_and_vassals
							change_county_control = $HELD_AND_VASSAL_COUNTIES$
						}
					}
				}
				else = {
					root.location.county.holder = {
						every_sub_realm_county = {
							custom = every_title_held_by_vassal_and_vassals
							limit = {
								this != root.location.county
							}
							change_county_control = $HELD_AND_VASSAL_COUNTIES$
						}
					}
				}
			}
			else_if = { # Only apply if HELD_AND_VASSAL_COUNTIES is not applied, prevent double tooltips
				limit = {
					$HELD_COUNTIES$ > 0
				}
				if = {
					limit = {
						$CAPITAL$ = $HELD_COUNTIES$ # Apply to capital if the values are the same
					}
					root.location.county.holder = {
						every_held_title = {
							custom = every_title_held_by_vassal
							title_tier = county
							change_county_control = $HELD_COUNTIES$
						}
					}
				}
				else = {
					root.location.county.holder = {
						every_held_title = {
							custom = every_title_held_by_vassal
							limit = {
								this != root.location.county
							}
							change_county_control = $HELD_COUNTIES$
						}
					}
				}
			}
		}
	}
}

As written in game/common/scripted_effects/04_dlc_ep2_tour_effects.txt.