-Sent acknowledgement of successful @option{PKT} (Base32-encoded hash)
-packet receipt. If @option{rx} is specified instead, then all
-@option{NODE}'s existing @code{rx} packets will be acknowledged.
+Send acknowledgement of successful @option{PKT} (Base32-encoded hash)
+packet receipt from @option{NODE} node. If no @option{-pkt} is
+specified, then acknowledge all packet in node's @code{rx} outbound
+spool. If @option{-all} is specified, then do that for all nodes.