While implementing the quick experiment for Steam desktop notification toasts size scaling (i.e. https://github.com/serious-angel/steam-client-custom-toasts, the source had the following object that may suggest supported devices by Steam, at least, for the current Steam desktop client version, with the Webpack transpiled chunks versioned as 2dcc5aaf7 (2025-10-26):
h = {
[-1]: "controller_none",
20: "controller_unknown",
0: "controller_unknown",
1: "controller_generic",
2: "controller_steamcontroller_gordon",
3: "controller_steamcontroller_unknown",