Used only if the attribute value is not available. If set to true, the inherited value is returned in this case, otherwise the default value.
defaultValue
{TAttributeType}
The value to return if a value hasn't already been specified.
Returns
{TAttributeType}
The attribute value if available and not set to "inherit"; the ancestors value for the same attribute if it exists and if either the attribute value is set to "inherit", or inherited is true; the default value otherwise.