Also if anyone is poking at this:

The old button-only version has four directional buttons on the left, assigned to pins 13-16.  The two buttons on the right are pins 1 and 2.

The new joystick version has a joystick on the left, assigned to pins 1, 2 and 8.  And four buttons on the right, pins 13-16.

Found it, here's the Makecode extension:

https://github.com/DFRobot/pxt-gamePad

I swear I was looking for this for hours yesterday.  Anyway Digikey (https://www.digikey.com/en/products/detail/dfrobot/DFR0536/8827829?s=N4IgTCBcDaICYDMBOAGArAZgGwgLoF8g) is showing the newer joystick version, but the documentation points to the old version.

The documentation for the joystick version is here: https://github.com/DFRobot/DFR0536_GamePad_V3.0_WIKI_EN