Help:$smwgDataTypePropertyExemptionList

is a configuration parameter that sets which datatypes are exempted from the property registration process. It was introduced in .CiteRef::gh:smw:1812

When a datatype is being exempted from the property registration process no corresponding property will be created allowing to directly add a data value to it. The reason is that doing so does brings no benefit since the datatype requires further definitions to operate using which holds a many values via a compound of properties defined with their respective datatypes.

Default setting
This means that by default the and  are exempted from the property registration process.