Split windows, like found in some IRC clients, would be nice.

I've thought about this in the past, but I don't know how it's supposed to interact with the sidebar. Any ideas?

Well, the way Weechat does it is when you create a split window (via /window split[vh]) is it just changes what channel you have selected in the sidebar, depending on which window you have focused.

Hmm, I suppose that could work.

If a window is split into 2 panes, does it get two tab bars?

I don't think Weechat can do tabs, so I'm not entirely sure. But I think tabs containing a configuration of split windows could work.

What gets displayed in the tab icon, etc., etc?

Sorry, not entirely sure what you mean.

Well, right now, each tab will display an icon, title, and unread count for the channel open on it. If tabs can contain split views, what goes in the icon, title, unread count etc.?

Here's how the i3 window manager does it. Not really sure how to explain it, but in i3, you can have workspaces which contains an unlimited amount of tabs, and those have a tree of splits. The title of the tab shows how the applications are split inside of the tab. Maybe something like that?

I would suggest doing ti the VS-code way. You would essentially have two tab-groups, one independent of the other. Each functions as its own "window". The last active tab group is treated just the same as the "tab-group" is being currently treated. Choose the other tab, and that becomes the "active" tab.

Here's a little example to refer to https://www.youtube.com/watch?v=ycTPdsnXFF8

I would also like to upvote this feature, and I like the idea of doing it the VS-code way.

I downloaded Ripcord yesterday, and I LOVE IT already.

I'll pay to support you, this feature was the first thing I found that I wished for.