[Feature Request] Allow the use of Proton without having Steam available.

[Kyuyrii]

Is your feature request related to a problem? Please describe.

I downloaded Rare and tried to use Proton, but it wasn't available. I discovered that I needed to install the Steam .deb file so that Rare could access its files, and only after that could I use Proton.

I thought it used steamrt3 without UMU, but that UMU Protonfixes window appeared (the one created with Zenity), so that doesn't seem to be the case.

This makes accessing Proton very difficult, especially considering that Steam isn't necessary to use Proton, with or without UMU.

Describe the solution you'd like

I would like to be able to choose a folder where versions of Proton are available (such as Proton-GE, Proton-Sarek, Proton-EM, Proton-CachyOS, UMU-Proton), without needing Steam, since there are other launchers and tools that transfer versions of Proton, and if possible, have the option of not using UMU.

Describe alternatives you've considered

Additional context

[loathingKernel]

I am considering how I want to solve this. Rare's steamrt integration is older than umu, in fact large part of umu's development was based on Rare's steamrt exploration and integration. The assumption is that for the most part Steam is present and configured, and it is an assumption that has been proven more or less true so far.

I am not sure I want to re-invent the wheel and make a downloader for arbitrary protons, we have two very good tools for that, protonup-qt and protonplus. I might start using umu though to download the runtimes and access them from there instead of Steam. Umu has the problem that it doesn't communicate to the user was is going on, but that is the kind of problem that I am in a place to solve myself for umu.

I do not think I want to implement loading protons from arbitrary directories, Rare already checks most of the common locations for them along its own, and can load them through flat vdf files too, instead of just directories. There are a few way an arbitrary location could be implemented with minimum friction, but I am not sure how useful or confusing it might be.

[Kyuyrii]

Would using UMU-Proton be a problem?

From what I've tested, when using UMU without specifying a Proton to be used, it starts downloading UMU-Proton.

UMU notifies you in the terminal that it's downloading UMU-Proton, and Rare shows several details about what's happening in the window it opens when starting a game. For example, I used UMU directly, without specifying the Proton to be used, and this appeared in the terminal:

INFO: umu-launcher version 1.3.0 (3.13.7 (main, Jan 22 2026, 20:15:57) [GCC 15.2.0])
INFO: No GAMEID set, using umu-default
INFO: steamrt3 is up to date
INFO: Downloading UMU-Proton-9.0-4e.sha512sum...
INFO: Downloading UMU-Proton-9.0-4e.tar.gz...
INFO: UMU-Proton-9.0-4e.tar.gz: SHA512 is OK
INFO: Extracting UMU-Proton-9.0-4e.tar.gz...
INFO: /home/nufluli/.cache/umu/tmpuwbdm8ut/UMU-Proton-9.0-4e -> /home/nufluli/.local/share/Steam/compatibilitytools.d
INFO: Using UMU-Proton-9.0-4e

If you're going to add something to UMU to indicate that UMU-Proton and steamrt3 are being transferred, I imagine a Zenity window would be sufficient.

[loathingKernel]

Yes, the terminal dialog that opens when you run a game is enabled on Linux by default exactly for that reason, to provide the user information that something is happening, that the application is not just "dead". That being said, using zenity is not what I am after, I generally from a UX point of view I want to avoid dialogs unless there is a reason to show them, I personally really dislike the zenity busy bar that protonfixes implemented, but alas it solves the problem for most people.

My goal would be to use umu to set up the runtimes using either a dedicated first time setup, or a form somewhere in the application to select and download certain runtimes. Once Rare is able to find umu's runtimes to satisfy the runtime requirements of the compatibility tools it discovers, they will be visible. Rare hides any compat tools that it can't figure out the runtime they require, the reason you couldn't find any Protons is because, without Steam, Rare couldn't find the runtimes the Protons it discovered needed, despite checking multiple directories, umu's compattool directory included.

I did not integrate with umu before because its development was slow, and it didn't do everything that I wanted it to do, for example, things like running the
runtime-less proton-cachyos, the ability to re-enter the runtime container, or even properly wait for the application to exit. As such I preferred to retain my local implementation thus far. I honestly would like to integrate with it once it is mature enough to do everything I want it to do. I will likely start considering full integration once it can report state and progress, likely through a unix socket. I have to figure out something out until then though.

So yeah, I am at this point where I have not decided yet if I want to scrap Rare's own steamrt handling and use umu, or find a way to neatly integrate them.

[loathingKernel]

So, I went ahead and added discovery of umu runtimes with 8f8326c . I have been postponing this for a while, thanks for kicking my butt into doing it. As it is now, umu still needs to be set up separately, but at least if it is found, Protons will be available to use without Steam being present. Umu's runtimes are preferred over Steam's as they are also generally newer than Steam's, unless the beta channels are used in Steam, so that's another benefit.

This issue should remain open for now until this is fully implemented.