The unrealircd.org/issued-by message tag communicates who is responsible
for issuing the command. For example for a forced nick change due to
Services, it will communicate this info in the NICK message.

This tag is only sent to IRC Operators and used intra-server (internally).

Syntax of the tag
==================
unrealircd.org/issued-by=SERVICES:<nick>@<server>
unrealircd.org/issued-by=OPER:<nick>@<server>:<oper_block_login>
unrealircd.org/issued-by=RPC:<rpc-user>@<server>[:optional_extra_login_info]

Example lines
==============
Forced NICK change by NickServ through SVSNICK server-to-server command:
@unrealircd.org/issued-by=SERVICES:NickServ@services.example.net :nick!user@host NICK Guest123456

Forced JOIN to #test by an oper using the SAJOIN command:
@unrealircd.org/issued-by=OPER:Oper1@maintest.example.net:OperAccount :nick!user@host JOIN #test

Forced MODE change on #test through the admin webpanel via the channel.set_mode call:
@unrealircd.org/issued-by=RPC:adminpanel@irc1.example.net:Syzop :irc1.example.net MODE #test +s