wanderer_give_random_commander_trait_effect

wanderer_give_random_commander_trait_effect = {
	random_list = {
		100 = {
			trigger = { NOT = { has_trait = logistician } }
			add_trait = logistician
		}
		100 = {
			trigger = { NOT = { has_trait = military_engineer } }
			add_trait = military_engineer
		}
		100 = {
			trigger = { NOT = { has_trait = aggressive_attacker } }
			add_trait = aggressive_attacker
		}
		100 = {
			trigger = { NOT = { has_trait = unyielding_defender } }
			add_trait = unyielding_defender
		}
		100 = {
			trigger = { NOT = { has_trait = forder } }
			add_trait = forder
		}
		100 = {
			trigger = { NOT = { has_trait = flexible_leader } }
			add_trait = flexible_leader
		}
		100 = {
			trigger = {
				NOT = { has_trait = desert_warrior }
				location = {
					terrain = desert
				}
			}
			add_trait = desert_warrior
		}
		100 = {
			trigger = {
				NOT = { has_trait = jungle_stalker }
				location = {
					terrain = jungle
				}
			}
			add_trait = jungle_stalker
		}
		100 = {
			trigger = {
				NOT = { has_trait = winter_soldier }
				location = {
					OR = {
						terrain = taiga
						geographical_region = world_tibet
						geographical_region = world_europe_north
						geographical_region = world_europe_east
						geographical_region = world_steppe
					}
				}
			}
			add_trait = winter_soldier
		}
		100 = {
			trigger = { NOT = { has_trait = reaver } }
			add_trait = reaver
		}
		100 = {
			trigger = { NOT = { has_trait = reckless } }
			add_trait = reckless
		}
		100 = {
			trigger = { NOT = { has_trait = holy_warrior } }
			add_trait = holy_warrior
		}
	}
}

As written in game/common/scripted_effects/00_courtier_guest_management_effects.txt.