Legal-hold state after the call. Undefined when not touched by this invocation.
Retention mode after the call. none means retention was cleared. Undefined if only legal-hold was touched.
B2 file ID of the version that was modified.
B2 file name the retention/hold was applied to.
Retention expiration timestamp (ms since the epoch). null when mode is none.
Result of retentionCommand: describes what was applied to the target version.