purchase_land_interaction_effect

purchase_land_interaction_effect = {
	# scope:actor = adventurer
	# scope:recipient = seller
	# purchased_titles = titles

	hidden_effect = {
		scope:actor = {
			if = {
				limit = { character:90028 ?= this }
				add_character_flag = hereward_settled_flag
			}
			if = {
				limit = {
					NOT = { has_trait = adventurer }
				}
				add_trait = adventurer
			}
			every_courtier = {
				set_variable = {
					name = former_camp_leader
					value = scope:actor
				}
				add_trait = adventurer_follower
			}
		}
	}

	# Determine hierarchy
	ep3_become_landed_save_liege_effect = {
		TITLE_GIVER = scope:recipient
		ALWAYS_INDEPENDENT = no
		TITLE_LIST = purchased_titles
	}
	# Purchase land specific
	# actual give recipient the gold
	scope:actor = {
		pay_short_term_gold = {
			gold = scope:purchase_land_cost
			target = scope:recipient
		}
	}
	# Resolve title, liege, government changes
	ep3_become_landed_transfer_effect = {
		TITLE_RECEIVER = scope:actor
		TITLE_LIST = purchased_titles
		TYPE = granted
		REASON = flag:purchased
		ENNOBLED_ADVENTURER = flag:yes
	}
	# Extra purchase land specific
	scope:actor = {
		stress_and_fulfillment_impact = {
			greedy = minor_stress_impact_gain
			lazy = minor_stress_impact_loss
		}
	}
	# Effects on land giver
	scope:recipient = { add_legitimacy = scope:purchase_land_legitimacy_cost }
	# Messages for nearby players
	create_landed_ruler_message_effect = {
		LANDED = scope:actor
		FLAVOR_CHAR = scope:recipient
		FLAVOR_TITLE = scope:target
		REASON = flag:purchased
	}
	# Hook
	if = {
		limit = { scope:offer_hook = yes }
		scope:recipient = {
			add_hook = {
				type = obligation_hook
				target = scope:actor
			}
		}
	}
	#Handle the government types
	if = {
		limit = {
			scope:recipient = { government_has_flag = government_is_mandala }
			#... we're lenient
			faith = { has_doctrine = doctrine_polytheist }
		}
		#Sort out the House shenanigans
		hidden_effect = {
			if = {
				limit = { is_house_head = no }
				house ?= {
					if = {
						limit = {
							house_head = {
								is_landed = no
								is_courtier_of = root
							}
						}
						set_house_head = root
					}
				}
			}
			else = {
				house ?= {
					if = {
						limit = {
							NOT = { has_house_aspiration_parameter = no_aspect }
						}
						set_house_aspiration = { type = no_aspect }
					}
				}
			}
		}
	}
}

As written in game/common/scripted_effects/07_dlc_ep3_scripted_effects.txt.