I don't know if it is possible to add the channel modes on the default mIRC Channel List window but i am sure it can be coded and replace it with your custom window, you need to create raws and aline the output of raws into an custom window and close the mIRC default channel list window.

Help details:

1. /help /window
2. /help /aline
3. /help raw events
4. /help /close

Raw numerics are: 321 322 323

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