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The path part contains a host specific object name, an optional version number, and an optional list of attributes. If these latter fields are present thy are separated from the host specific object name and from each other by the characters "%00" (percent, zero, zero), this being and escaped string terminator (null). If the optional list of attributes is provided, the version number must be present, but may be the empty string (i.e. the first attribute would be separated from the host specific name by "%00%00"). External Prospero links are represented directly as URLs of the underlying access method and are not represented as Prospero URLs.