In the screenshot that is attached to the tweet it says “RetroBrowser” is the name of the core? So I went looking and found this: https://github.com/libretro/minibrowser It looks dead to me, what happened? :’(
That was just something bparker was playing around with. I’ll ask him if he plans to ever polish it up.
I sure hope so. 
Qt no longer works on it so if we were to use it, we’d really be stuck with a webbrowser that is going to age faster than milk. So we are not sure if it’s worth the time and trouble to keep working on it, and there don’t seem to be any viable solutions.
Why doesn’t Qt no longer work on it? Is it the licensing or something? Or did you mean that Qt is outdated? If so, why no Qt Quick or a replacement?