+Numeric replies
+---------------
+
+280 - RPL_ACCEPTLIST
+--------------------
+:<server> 280 <nick> <accepted1> <accepted2> ...
+
+This numeric is used to indicate to a client the list of nicknames they are
+accepting. At most 15 accepted nicknames may be included; if this is exceeded
+multiple RPL_ACCEPTLIST must be sent.
+
+281 - RPL_ENDOFACCEPT
+---------------------
+:<server> 281 <nick> :End of /ACCEPT list.
+
+This numeric is used to indicate to a client the end of an accept list.
+
+456 - ERR_ACCEPTFULL
+--------------------
+:<server> 456 <nick> :Accept list is full
+
+This numeric is used to indicate to a client that their accept list is full
+and one or more nicks could not be added.
+
+457 - ERR_ACCEPTEXIST
+---------------------
+:<server> 457 <nick> <target> :is already on your accept list
+
+This numeric is used to indicate to a client that the given nick was already
+on their accept list.
+
+458 - ERR_ACCEPTNOT
+-------------------
+:<server> 458 <nick> <target> :is not on your accept list
+
+This numeric is used to indicate to a client that the given nick was not on
+their accept list.
+
+716 - ERR_TARGUMODEG
+--------------------
+:<server> 716 <nick> <target> :is in +g mode (server-side ignore.)
+
+This numeric is used to indicate that a message (PRIVMSG) the client sent
+could not be delivered because of CallerID restrictions. The <target>
+parameter is the target user's nick.
+
+717 - RPL_TARGNOTIFY
+--------------------
+:<server> 717 <nick> <target> :has been informed that you messaged them.
+
+This numeric is sent after 716 if the target user was notified of the message.
+
+718 - RPL_UMODEGMSG
+-------------------
+:<server> 718 <nick> <target> <user>@<host> :is messaging you, and you have umode +g.
+
+This numeric is sent when a message (PRIVMSG or NOTICE) sent to the user is
+blocked by CallerID, at most once per minute.
+
+Problem: hybrid uses the following form instead
+:<server> 718 <nick> <target>[<user>@<host>] :is messaging you, and you have umode +g.
+which is ambiguous if the user may contain a [ and in the author's opinion ugly.
+