LANCommander.Redistributables.UmuLauncher

Automatically built LANCommander redistributable import package (.LCX) for umu-launcher.

umu-launcher runs Windows games on Linux through Proton. It is the standalone entry point into Valve's Steam Linux Runtime, so a non-Steam game gets the same container, the same Proton build and the same per-game fixes Steam applies to its own library — without Steam installed. Attach it to Windows-only games that your Linux clients need to run.

This is a compatibility shim, not a runtime installer. Rather than installing something a game then finds on its own, it wraps the game's launch command.

Install it

Download the .lcx asset from the latest release and import it through your LANCommander server's Redistributables page, or from the CLI:

LANCommander.Launcher.CLI Import --Path LANCommander.Redistributables.UmuLauncher-v<version>.lcx --Type Redistributable

Then assign it to the games that need it, either from the game's Redistributables field or from this redistributable's Games field.

Re-importing a newer release updates the existing entry rather than creating a second one, because the identifiers in redistributable.yml are stable across releases.

Alternatively, import once and let it update itself: the package ships a Package script, which a LANCommander server runs on a schedule to pull new versions straight from this repository's releases.

Client requirements

Linux only	Every client-side script is marked Platforms: Linux. See the warning below about mixed-platform games.
Python 3.10+	umu-run is a Python zipapp: it bundles umu and its dependencies but not an interpreter. The Install script fails with a clear message if python3 is missing.
Disk and bandwidth	The first launch downloads Proton and the Steam Linux Runtime — expect 1–2 GB, with no progress shown in LANCommander. Pre-warm clients before an event, or see Update the Runtime below.

What it installs

Only umu-launcher itself, and only into the game's own metadata directory at {InstallDir}/.lancommander/{RedistributableId}/Files/. Nothing is written to the game directory, to ~/.local/bin, or anywhere system-wide.

File
umu-run	The upstream zipapp, redistributed unmodified (~420 KB)
COPYING.txt	The upstream GPLv3 text

Proton and the Steam Linux Runtime are not bundled — umu-launcher downloads those itself on first launch, into its own XDG directories, where they are shared across every game.

The game is then launched through a command template:

python3 "{InstallDir}/.lancommander/<id>/Files/umu-run" "{exe}" {args}

Options

Nine options, all of which reach umu-launcher as environment variables.

Option		Default
Game Identity
GAMEID	Identifier umu uses to find per-game Proton fixes in its games database	umu-default
STORE	Storefront this copy came from — only meaningful alongside a real Game ID	(unset)
WINEPREFIX	The game's virtual Windows install: registry, runtimes, saved files	{InstallDir}/.umu
Proton
PROTONPATH	A path, version name (GE-Proton9-5) or codename (GE-Proton)	(unset — umu uses UMU-Proton)
PROTON_VERB	How Proton starts the executable	waitforexitandrun
Runtime
UMU_RUNTIME_UPDATE	Whether to check for a newer Steam Linux Runtime each launch	1
UMU_HTTP_TIMEOUT	Seconds to wait on each download request	5
UMU_HTTP_RETRIES	How many times to retry a failed download	3
Diagnostics
UMU_LOG	umu's own logging — set to 1 or debug when a game will not start	0

Administrators can override any of these per game from the game's Redistributables page. Values resolve as schema default, then per-game value, then per-action override.

Two are worth setting deliberately:

• GAMEID is what unlocks per-game Proton fixes. Look the title up in the umu database and set its umu- id per game; the default applies no fixes at all.
• WINEPREFIX defaults to a prefix inside the game's own directory, which is the one place this package deviates from upstream (umu would use $HOME/Games/umu/$GAMEID). That keeps games isolated from one another and lets the Uninstall script clean the prefix up. Point several games at one path to share a prefix — the Uninstall script will then leave it alone, since it only ever deletes a prefix inside the game directory it is uninstalling.

For an event with poor connectivity, set UMU_RUNTIME_UPDATE to 0 to pin every client to the runtime it already has.

UMU_NO_PROTON is deliberately not exposed. umu tests it with != "1" in one place and with bare truthiness in another, and "0" is truthy in Python — an administrator switching it "off" would switch it on.

Mixed-platform games

GuestPlatforms gates which actions the launcher offers, but the command template is applied on whatever host the game launches from. Attaching this redistributable to a game that Windows clients also launch will break that game on Windows. Keep it on Linux-only entries, or on games your Windows clients do not run.

What is in the package

Path
Manifest.yml	Redistributable metadata, including the embedded option schema
Archives/{guid}	A ZIP of the payload, extracted into the game's .lancommander metadata directory
Scripts/{guid}	One entry per PowerShell script

How this repository works

File	Purpose
redistributable.yml	Identity, payload source, stable script GUIDs
source.ps1	Resolves the upstream release and extracts the zipapp from its tar
Schema.Overlay.yml	The whole option schema, written by hand
OptionSchema.yml	Generated from the overlay. Do not edit by hand
Scripts/*.ps1	DetectInstall, Install, Uninstall and the server-side Package updater
LICENSES/	Upstream attribution and license text

Unusually for a redistributable in this family, Schema.Overlay.yml is not curation layered over a parsed config — it is the schema. umu-launcher reads no configuration file (it accepts a TOML file only when passed --config), so ConfigPaths is empty and every option is hand-written.

OptionSchema.yml is still generated, and the build fails if the committed copy does not match what the overlay produces. To regenerate it locally:

Import-Module <path-to>/LANCommander.Redistributables/module/LANCommander.Redistributables
Invoke-RedistributableBuild -RepositoryPath . -UpdateSchema

Edit Schema.Overlay.yml; never edit OptionSchema.yml, since the next rebuild overwrites it.

Staying current

A scheduled workflow checks umu-launcher for new versions. When one appears it rebuilds the payload from the new release and opens a pull request; merging it publishes the release.

Because the option set is hand-written rather than parsed, a new environment variable upstream adds will not appear on its own — it has to be added to Schema.Overlay.yml. Upstream documents them in docs/umu.1.scd, which is worth a look when a release bumps the minor version.

Licensing

The scripts and workflows here are MIT licensed. umu-launcher itself is GPLv3 and is not ours — see LICENSES/NOTICE.md for attribution, the obligations we carry, and where to obtain the corresponding source.