Another success with an "Unsupported" title:
TrackMania2 Valley.
The really strange thing is that
TrackMania2 Stadium is listed as Playable, but both games use the same launcher and are essentially the same game with different content. In fact, there's no point in installing both games since you can install and launch into any of the content packs from the launcher. So I could just install TrackMania
2 Stadium and play Valley content from it. Or I can install TrackMania
2 Valley and play Stadium content from it. I really don't understand why one is considered Unsupported while the other is considered Playable. They both seem fully playable to me on Deck.