That is fully fine, I guess the code is copied from my gintro README, but I am not responsible for it, I was not even aware that gintro is mentioned there. So people may feel free to remove gintro references and replace with other GUI toolkits. I am not even sure if GUI examples belongs to a wikipedia page at all -- and we have more than a dozen of Nim GUI toolkits, we can not gave examples for all, so maybe better let then out fully.
For your remarks about let/var and init() -- if you are really interested in details you may consult the gintro readme, the GTK4 book and the Nim book.
