I found it in a tweet and I was pretty sure it was photoshopped silliness but people were acting as though it was a real thing. I had to google to confirm what's what...
Teenage Engineering's tiny handheld TX-6 mixer offers an instrument tuner | Engadget
It also has built-in synth and sequencer capabilities.
This is also a pet peeve of mine. I'm sure it carried over from mobile first web design.