This is a very attractive TUI. Nice job!

Agreed. I wonder if it's a custom TUI engine or leveraging a framework?

They are using Textual.

https://textual.textualize.io/

thank you!

Looks like Textual[1] -- the buttons are always a giveaway

[1] https://github.com/Textualize/textual

Dunno, I put it in the title.