The ( slimmer ) owner teaches latte art.
If not too busy when you order a latte you can enquire if can bring you through. The more latte u order the more time * with * her
Vietnamese kopi mostly Robusta but depending on roasters they do also mix other stuffs e.g cacao during the roasting to give that additional flavor.
Many many years ago their coffee industry was (unfairly) "criminalized" for burning rubber tyres during roasting for that different taste. But so many years have passed I also not sure if it is/was an urban legend anymore.
I do enjoy Vietnamese coffee.