On some places, metadata values are interpreted as a truth value.

Every character sequence that begins with a ""0"", ""F"", ""N"", ""f"", or a ""n"" is interpreted as the boolean ""false"" value.
All other values are interpreted as the boolean ""true"" value.

However, there is no full support for a boolean type.
Such values are interpreted as a [[string value|00001006033500]], e.g. with respect to comparing and sorting.