Something weird just happened to me: I mis-typed a keyboard shortcut, hitting the wrong keys, and a new notebook opened up with a Python prompt! Just for grins, I tried entering some simple Python code into the cell and evaluating it, and sure enough, it produced correct output.
The little python-logo box to the left of the input box, if clicked, produces a drop-down menu that lets me choose Python or NodeJS.
I've done some googling, and discovered that Mathematica has a new experimental "external evaluation system". Cool! However, I have been unable to figure out what keystroke I hit that made this little gem appear. All the Mathematica docs say is that one can use the relatively clumsy
Does anyone know how to produce this special input cell?