[oefrha]

Yes, it's an iframe embedding a third party service, https://github1s.com/. "It appeared sufficiently like I was actually in a VSCode instance" because it is a VSCode instance.

Source code here: https://github.com/conwnet/github1s

Discussed a while ago: https://news.ycombinator.com/item?id=26083919

[da39a3ee]

Ohhh right, thanks! I did see that HN discussion so I should have spotted the github1s URL. Lots of fun tricks going on...

[oh-renovamen]

Yeah, github1s is amazing!