Custom Css
As a programmer it would be nice to change the css like you can with Discord.
Changing the app.asar seems to break everything, possibly because of binary in the file.
My current issue is for example that tabs have like a fixed min size, making you have to click on the little arrows when you idle in many chats, which is quite tedious. I would prefer to have it like a browser will make tab smaller and smaller.
I like the idea, but would choosing between a streamer's icon and their name (or both) suffice for this? I'm envisioning a toggle within the settings so all tabs are either the streamer icon (see below), the icon and the name, or just the name. It could be expanded at a later date to be "smart" and if the drawing of the tab would overflow the container, it will switch to streamer icons.
King Gothalion's Streamer Icon:

SyntaxSe7en's Streamer Icon:

Thoughts?
I know that Firefox allows you to use the scrollwheel (up/down) to scroll the tab bar when there are more tabs than it can display. Could we do the same here? - Having just checked, we already do. Scrollwheel while the pointer is over the tab bar will scroll it.
+1 for custom css. At least I want modify tabs =) Sometimes I confuse tabs.