If a channel has mode "+l 123", the "123" value will be included in the window title. I'd like to duplicate that behavior for other channel modes in a mIRC script I use when connecting to Twitch.

First, when connecting to the Twitch server, I simulate a 005 message being received since Twitch doesn't send its own and I had assumed this is how mIRC knew when to display a value for a channel mode in the window title:

Code
.parseline -itqp : $+ $server 005 $me PREFIX=(qaohv)~&@%+ CHANMODES=b,k,lFHS,mEU MODES=6 :are supported by the TMI script

I've echo'd $chanmodes and verified that mIRC correctly parsed that 005 event and set its chanmodes identifier accordingly.

Later, I use parseline to simulate either a 324 message (when joining a channel) or a "MODE" message (if an action happens while already joined). Example raw message that appears in the /debug window:

Code
<- :tmi.twitch.tv 324 bradg #testchannel +F 35

I can see that mIRC adds "+F" in the window title... but no matter what I try, it never shows the value. If I try setting "+l 123", however, I see the "123" value show up in the title.

Is mIRC hardcoded to only recognize specific channel modes whose values should be added to the window title?