in spreadsheet/JsonConverter.bas [664:675]
Private Function json_IsUndefined(ByVal json_Value As Variant) As Boolean
Select Case VBA.VarType(json_Value)
Case VBA.vbEmpty
json_IsUndefined = True
Case VBA.vbObject
Select Case VBA.TypeName(json_Value)
Case "Empty", "Nothing"
json_IsUndefined = True
End Select
End Select
End Function