How do I use this?

Well, there's a release, but it won't follow the Mafia release exactly until I figure out an automated build process.

The release tag is the same as the Mafia tag used.

Otherwise, you can build a Flatpak file with the latest Mafia tag with some steps:

Download This Repository

Clone it locally, and then change to that directory. All following steps assume being in the repository's directory.

Install Dependencies

You'll need flatpak and flatpak-builder available. If on Steam Deck, flatpak is there, and you can get the flatpak-builder as a Flatpak here: https://flathub.org/apps/org.flatpak.Builder

Download Mafia

Go here: https://github.com/kolmafia/kolmafia/releases
Download the .jar file (example: KoLmafia-28579.jar)
Move it from wherever you downloaded it to the repository directory, and rename it to mafia.jar. The build steps expect a mafia.jar file.

Build the Flatpak Files

Run this command from the repository directory.

flatpak-builder --force-clean --user --install-deps-from=flathub --repo=repo --install builddir com.theinternetvagabond.kolmafia.yml

Additionally

You can build a .flatpak file. This file is a bit like a portable Flatpak install file, and is what I upload to the Releases.

(This assumes you've run the flatpak-builder command above) Build the .flatpak file: flatpak build-bundle repo kolmafia.flatpak com.theinternetvagabond.kolmafia

The benefit of building the .flatpak file is you can move it around to install elsewhere. If you, for example, build the file on a desktop, you can then transfer it to a Steam Deck, and install it there.

Run/Install the Flatpak

If you're on the machine you built the Flatpak from, it should now show up in the application menu. If it doesn't, you can try building the .flatpak file and installing it as below. Once installed, you should be able to just click the menu option.

If you want to run the Flatpak that was build above in the flatpak-builder command: flatpak run com.theinternetvagabond.kolmafia

To install the .flatpak file: flatpak install -u kolmafia.flatpak (Note: This will likely tell you it's already installed if tried on the machine that built it.)