get_random_location_effect

get_random_location_effect = {
	hidden_effect = {
	    random_list = {
	        1 = { # Library
	            trigger = {
	                NOT = { government_has_flag = government_is_tribal }
	            }
	            set_variable = {
	                name = random_location
	                value = 0
	            }  
	        }
	        1 = { # Garden
	            set_variable = {
	                name = random_location
	                value = 1
	            }  
	        }
	        1 = { # Corridor
	            set_variable = {
	                name = random_location
	                value = 2
	            }  
	        }
	        1 = { # Council Chamber
	            trigger = {
	                NOT = { government_has_flag = government_is_tribal }
	            }
	            set_variable = {
	                name = random_location
	                value = 3
	            }  
	        }
	        1 = { # Throne Room
	            set_variable = {
	                name = random_location
	                value = 4
	            }  
	        }
	        1 = { # War Camp
	            trigger = { is_in_army = yes }
	            set_variable = {
	                name = random_location
	                value = 5
	            }  
	        }
	    }
	}
}

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