https://www.raspberrypi.com/software/raspberry-pi-desktop/

It looks like Raspberry Pi Desktop is based on Debian Bullseye:

Debian Bullseye with Raspberry Pi Desktop
Release date: July 1st 2022
System: 32-bit
Kernel version: 5.10
Debian version: 11 (bullseye)

Installation of Raspberry Pi Desktop from the image on USB seemed successful and the machine boots to a desktop OK.

I’ve then tried running the MagicMirror install script from https://github.com/sdetweil/MagicMirror_scripts

but this gets to the section installing correct version of node and npm, please wait and fails with error messages at the terminal

ERROR: npm v10.1.0 is known not to run on Node.js v12.22.12.  This version of npm supports the following node versions: `^18.17.0 || >=20.5.0`. You can find the latest version at https://nodejs.org/.

ERROR:
/usr/local/lib/node_modules/npm/lib/utils/exit-handler.js:19
  const hasLoadedNpm = npm?.config.loaded

followed a bit later by

node failed to install, exiting

The RPi desktop installation instructions included allowing updates as part of the install process, so just in case that was causing issues I’ve tried:

• MM install via script on a fresh RPi Desktop install (allowed updates during install)
• MM install via script on a fresh RPi Desktop install (skipped updates during install this time)

but I’m seeing the same npm error during the MagicMirror installation on both.

Thanks for reading this far and any suggestions! - let me know if there’s anything else I should try : )