can_use_befriend_scheme_trigger

can_use_befriend_scheme_trigger = {
	OR = {
		custom_tooltip = { 
			text = sp_befriend_chaplain_tt
			has_fulfillment_parameter = sp_befriend_chaplain
			exists = cp:councillor_court_chaplain
			$TARGET$ = { this = prev.cp:councillor_court_chaplain }
		}
		custom_tooltip = { 
			text = sp_befriend_hor_tt
			has_fulfillment_parameter = sp_befriend_hor
			exists = rite.head_of_rite
			$TARGET$ = { this = prev.rite.head_of_rite }
		}
		custom_tooltip = {
			text = sp_befriend_hof_tt
			has_fulfillment_parameter = sp_befriend_hof
			exists = faith.religious_head
			$TARGET$ = { this = prev.faith.religious_head }
		}
		AND = {
			house ?= { has_house_head_parameter = unlock_befriend_scheme }
			is_house_head = yes
		}
		has_perk = befriend_perk
		AND = {
			dynasty ?= {
				has_dynasty_perk = fp1_adventure_legacy_5
			}
			target_is_vassal_or_below = $TARGET$
		}
		culture = { has_cultural_parameter = automatic_befriend_access }
		any_character_struggle = {
			involvement = involved
			has_struggle_phase_parameter = struggle_unlocks_befriend_schemes_for_everyone
		}
		AND = {
			government_has_flag = government_is_clan
			is_in_same_clan_as_trigger = { CHARACTER = $TARGET$ }
			house = { has_house_unity_stage = harmonious }	
		}
		government_has_flag = government_is_nomadic	
	}
}

As written in game/common/scripted_triggers/00_scheme_triggers.txt.