add_random_tiered_trait_xp_effect

add_random_tiered_trait_xp_effect = {
	save_scope_value_as = {
		name = level_1_possible
		value = flag:$LEVEL_1$
	}
	save_scope_value_as = {
		name = level_3_possible
		value = flag:$LEVEL_3$
	}
	if = {
		limit = { has_trait = $TRAIT$ }
		random_list = {
			15 = {
				trigger = { scope:level_1_possible = flag:yes }
				add_trait_xp = {
					trait = $TRAIT$
					value = {
						integer_range = {
							min = small_lifestyle_random_xp_low
							max = small_lifestyle_random_xp_high
						}
					}
				}
			}
			10 = {
				add_trait_xp = {
					trait = $TRAIT$
					value = {
						integer_range = {
							min = medium_lifestyle_random_xp_low
							max = medium_lifestyle_random_xp_high
						}
					}
				}
			}
			5 = {
				trigger = { scope:level_3_possible = flag:yes }
				add_trait_xp = {
					trait = $TRAIT$
					value = 100
				}
			}
		}
	}
}

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