valid values on merci_import.php

On merci_import.php

In the section on Data structure for bucket/resource item nodes, it lists the following valid values.

default_availability (integer): The reservatioin availability of the item. Valid values: 1 (available) | 2 (unavailable) | 3 (strictly available) | 4 (strictly unavailable)

These valid values do not intuitively make sense.