Basically, some different apps were linked to the official steamVR app. These apps are hidden, but the data miner was able to grab some assets from them that included some custom art for Waydroid, which is a Linux program that lets you run Android apps on Linux.
Additionally, I've seen comments saying that some valve devs have been making pull requests for the Waydroid github, but I don't actually have a proper source for that.
On Bazzite I believe people use Firefox installed as Android app, so they can simply switch to it for game guides etc, while playing a game, in GameScope/Big Screen/GameMode™
I'm too lazy to test, because I just run it as my daily driver on my Desktop.
But you can do the same with a normal desktop Firefox, none of those things prevent you from switching windows to check things. There must be some other reason why it's run as an Android app.
Some games will refuse to work on Linux but their Android port might work.
If Valve can make this process seamless, it could be a gamechanger. Example, Genshin Impact, Wuthering Waves etc
Before the steamdeck came out, I've been actually thinking about buying an android handheld console. The fact that the most android games were pay2win convinced me to wait for something better.
However, getting an android app support, that's reliably set up, by someone else than me, and basically for free would still be nice!