User data. The server returns the contents of this field to the client in response to req=userdata.
Text string value. It is recommended to use property data formatting. If property data formatting is not used, text string must not contain the '=' character.
The zoom, spin, and brochure viewer clients assume this field to use property data formatting. These clients use this field for viewer configuration and customization. See the viewer documentation for details.
This field participates in text string localization. Refer to Text String Localization in the HTTP Protocol Reference for details.