Runtimes, distributions and architectures

Where a Luma app runs, how it gets there, the Luma runtime and remote, what differs on other distributions, and which CPU architectures the remote carries today.

Where your app runs

Where	How it installs	What it runs with	Looks like
Luma	From Depot, as a Flatpak from the Luma remote	The `org.projectluma.Platform//44` runtime, which carries LumaUI	Luma
Other distributions with Flatpak (Fedora Workstation, Ubuntu, Debian, Arch, openSUSE and others)	`flatpak install` from the Luma remote, a `.flatpakref`, or a software center that opens one	The same Luma runtime inside the sandbox	Luma

LumaUI draws a Luma app’s window and components itself, so the same Flatpak looks and behaves the same on Luma and on another distribution. Luma-specific system features are only present on Luma: the Semantic Broker and Live Extensions, for example. Your app must keep working without them.

LumaUI is not packaged for other distributions, so a LumaUI app cannot be shipped there as a native RPM or DEB. Use the Flatpak.

The Luma remote


Repository	`https://dl.simplyluma.com/repo/` (OSTree, signed summary and commits)
Remote file	`https://dl.simplyluma.com/luma.flatpakrepo`
Per-app install file	`https://dl.simplyluma.com/apps/<app-id>.beta.flatpakref` for an app on the `beta` branch, `https://dl.simplyluma.com/apps/<app-id>.flatpakref` for one on `stable`
Branches	`stable` (the remote’s default) and `beta`. Most of Luma’s apps are on `beta` today.
Architectures	`x86_64` only for now
Signing	A dedicated Luma Depot OpenPGP key. The public key is in the `.flatpakrepo` file.

On a system with Flatpak:

Shell

flatpak remote-add --if-not-exists luma https://dl.simplyluma.com/luma.flatpakrepo
flatpak install luma org.projectluma.Tide//beta
# or, for one app:
flatpak install --from https://dl.simplyluma.com/apps/org.projectluma.Tide.beta.flatpakref

To build against the Luma runtime, install the runtime and the SDK:

Shell

flatpak install luma org.projectluma.Platform//44 org.projectluma.Sdk//44

Runtimes

Ref	What it is
`org.projectluma.Platform//44`	The runtime. Built from Fedora 44’s Flatpak runtime package set, with Luma’s builds of GTK 4 and libadwaita, LumaUI (`luma-developer-platform`), the Figtree font and the Prairie icon theme.
`org.projectluma.Sdk//44`	The SDK for `flatpak-builder`. It adds the LumaUI headers and `pkg-config` files and the `luma` command.
`org.projectluma.Platform.Locale`, `org.projectluma.Platform.GL.default`	The runtime’s translations and default graphics drivers. Flatpak installs them with the runtime.
`org.projectluma.Platform.Office`	Extension with LibreOfficeKit 26.2 for document apps.

The branch, 44, matches the Fedora release the runtime is built from.

The GNOME runtime in the SDK template

luma new still writes a Flatpak manifest on org.gnome.Platform//50 that builds luma-developer-platform as its first module from a source tag. That source repository is not publicly reachable, so the generated manifest does not build as it is, and the GNOME runtime does not carry Figtree or the Prairie icons. Switch runtime, sdk and runtime-version to the Luma runtime and remove that module; see project layout.

Presentations on Luma

One binary serves every Luma device. LumaUI tells your app how it is being presented through LumaContext (C) and AppContext (Python), read from the environment:

Variable	Values	Default
`LUMA_DEVICE_CLASS`	`desktop`, `tablet`, `handheld`	Read from `/etc/luma-device-class`, else `desktop`
`LUMA_PRESENTATION_MODE`	`windowed`, `fullscreen-mobile`	`fullscreen-mobile` on a handheld, else `windowed`
`LUMA_INPUT_MODE`	`pointer`, `touch`	`touch` on a handheld, else `pointer`

Set these yourself to test a phone presentation on a desktop:

Shell

LUMA_PRESENTATION_MODE=fullscreen-mobile LUMA_INPUT_MODE=touch python3 src/main.py

Inside a Flatpak, /etc is the runtime’s, not the host’s, so the app cannot read the host’s /etc/luma-device-class. Use the environment variables there.

Architectures

Architecture	Status
`x86_64`	Supported. The Luma remote carries `x86_64` runtimes and apps.
`aarch64`	Not on the Luma remote yet.

luma release-check asks for passing evidence on both x86_64 and aarch64 before an app is a Native candidate (see luma-app.toml), so avoid code that assumes one architecture. Luma isn’t built for aarch64 yet, so no app can pass that check today.

What changes between Luma and elsewhere

Feature	On Luma	Elsewhere, on the Luma runtime
Luma window, islands, identity	Yes	Yes
Figtree and Prairie icons	Yes	Yes, from the runtime
Portals	Luma’s portal configuration, including Luma’s Open With and screen sharing choosers	The host’s portal backends (GNOME, KDE and others)
Light, dark, high contrast	Follows Luma settings, including the Frost and Glass materials	Follows the host’s light or dark preference (the `org.freedesktop.appearance` color scheme); Frost and Glass are Luma settings and are not used
Semantic Broker, Live Extensions	Available	Absent; your app must not require them
Presentation context	Read from the environment and the device	Defaults to desktop, windowed, pointer