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- Key: the name of the field (e.g. "URL")
- Value: the actual value, (e.g. "http://tdar.org")
- Type: the data type of annotation value; either "text", "numeric", or "formatted string"
- Format: For annotations of type "formatted string". This would be describe the format that the value must conform to. For example, the format for a phone number could be "(XXX)XXX-XXXX".