Hello there,
wrote a rather long question on StackOverflow, but it might be getting more attention here 
— ruby - Programmatically populating GtkTreeView in Glade created UI - Stack Overflow
In short, I am stuck at populating GTKTreeView / GTKListStore from a Window / Application / ApplicationWindow class.
Pls read the full, linked question before answering, or you might answer on StackOverflow ¯_(ツ)_/¯
According to this tutorial you use bind_template_child("config_tree_view") inside init and then you can access it via config_tree_view. There is also an example program using GTK templates (same one from the tutorial). (I’ve never used ruby so I can’t help with specifics.)
Thank you for the time you’d put into it. I got very similar solution from ChatGPT an hour before or so 
It’s funny the method is on the ruby-gnome project, because I was looking at that page, but I was probably not searching the right keywords
Just FYI, it’s the other way around. In my local time (CEST, UTC+2), I answered 19:36 but your StackOverflow answer was at 20:48 (That Z in 18:48Z in StackOverflow means UTC time). Also, when I answered, your answer definitely didn’t exist. But it’s solved so no need to further care about this.
1:0 For European human beings 
Skynet can go pouring terminators from one bottle to another Thank you for clarifying I really did not notice the Z on StackOverflow.