This app is specifically installing software using devkit tools, and registering games to Steam as a devkit game rather than an external application.

There's also been some question on how easy it will be for users to add Android APKs. It may be as simple as picking the Lepton compatibility layer, or it may be only available to devs atm. Either way this is the first thing I've seen that's saying users can definitely install their own android apps.

Also seems like vibecoded slop....

Developers have obviously had the Steam Frame for a while. Of course they want ways to make it easier to install things, and consumers will also want that soon enough.

Plenty of people have had them for months; just not the general public.

Similar software exists for the Deck. It's not a requirement for installing linux applications but it does make it easier to add links to the steam big picture interface and manage the cover art. The Frame also has the added complexity of supporting android APKs.

This is mostly meant to make it easier to install software from a separate PC vs having to install it from the Frame itself. That said, it is installing the software into steam as a steam dev build, which goes beyond the usual "add a non-steam application". I'm also not sure if users can add Android APKs to steam yet (to be run with Steam's Lepton), but this will allow that.

Per Wikipedia:

Sideloading is the process of transferring files between two local devices, in particular between a personal computer and a mobile device such as a mobile phone, smartphone, PDA, tablet, portable media player or e-reader.

And then a little bit later down:

The use of the term "sideloading" to describe downloading and installing an app outside of sanctioned means is controversial and not universally accepted.[1]