System76 COSMIC desktop Beta and Pop!_OS 24.04 LTS Beta now available

Two huge bits of news from System76, as they've released a Beta for both the new COSMIC desktop and Pop!_OS 24.04 LTS bringing lots of goodies.

I do find it interesting how System76 develop their own hardware, and run their own Linux distribution and now they're firmly getting into the Desktop Environment game with COSMIC designed for other vendors (distros and other organisations) to customize it. The official COSMIC page notes how it's "Best for users, best for your product" with the customization it allows.

From the press release:

System76 has been building COSMIC to propel the Linux desktop to new heights of user empowerment. It will replace their custom version of the GNOME DE on Pop!_OS to reimagine the desktop environment and the value it provides. Pop!_OS 24.04 LTS with COSMIC includes a custom theming system, customizable panels UI, enhanced workspaces system, streamlined tiling and keyboard shortcuts, and new core apps.

COSMIC is about empowering users to easily create their preferred workflow, emphasizing customizability to create the best, most consistent and flexible experience available. System76 understands that users know best how to use their computer for success. By enabling their personal preferences, they can remove obstacles to focus and empower themselves to unleash their potential.

With COSMIC, users can make their UI single- or dual-panel, workspaces horizontal or vertical, tiled or floating, dynamic or pinned (static), add new keyboard shortcuts, change Caps Lock, arrange applets (features on panels), create and share themes, and even add custom fonts or icons.

It comes with a bunch of the expected core desktop applications designed for COSMIC including COSMIC Settings, COSMIC Files, COSMIC Store, COSMIC Terminal, COSMIC Edit, and COSMIC Player. More COSMIC apps can be found in the Store's Explore page in the Made For COSMIC section.

System76 are keen to talk up how they built it with Rust, from the press release:

COSMIC is written from scratch in Rust, a programming language System76 engineers loved working with for its readability, stability, maintainability, and memory safety; many modern computer vulnerabilities happen in the system’s memory, and Rust makes it easy to write memory-safe code. As a newer language, this required a lot of groundwork in building the fundamental capability to create a desktop environment in the first place. System76 needed to build a complete toolkit of high-level components with deep platform integration, all designed to create a consistent look and feel for the COSMIC desktop environment. That effort resulted in the libcosmic toolkit, a robust, responsive set of widgets that adhere to the specific COSMIC design language. This includes buttons, sliders, text inputs, and other elements that are styled to match the rest of the desktop.

During development, the team even had to build basic features like text rendering, drag-and-drop, clipboard support, a full-featured compositor and support for input methods. But with such a modern codebase, System76 was able to avoid the significant technical debt that comes with generations of legacy code that complicates other desktop environments.

The COSMIC Beta is available with the Pop!_OS 24.04 LTS Beta and for testing in Fedora, NixOS, Arch, CachyOS and others.

As for the Pop!_OS 24.04 LTS Beta, System76 supplied some release notes:

• Pop!_OS 24.04 LTS Beta includes the new COSMIC Desktop Environment designed and developed by System76. COSMIC DE is largely feature complete for the first release and development focus has turned to bug fixes for the final release. ● This is a beta release and some bugs are expected.
• Some GNOME apps are replaced by COSMIC apps
  • GNOME Files (Nautilus) > COSMIC Files
  • GNOME Terminal > COSMIC Terminal
  • GNOME Text Editor > COSMIC Text Editor
  • GNOME Media Player (Totem) > COSMIC Media Player
• Pop!_Shop is replaced by COSMIC Store
• Key components
  • COSMIC Epoch 1 Beta
  • Linux kernel 6.16.3
  • Mesa 25.1.5-1
  • NVIDIA Driver 580
  • libwayland/libwayland-client 1.23.1-3
  • libdrm 2.4.125-1
• Dragging and Dropping files from Wayland apps to X11 apps is not currently supported. For instance dragging files from COSMIC Files to Slack. Use the applications upload option as a work-around until the feature is added.
• On distributions other than Pop!_OS, Firefox may need a configuration flag set to match COSMIC theming
  • Go to about:config and set widget.gtk.libadwaita-colors.enabled to false
• Google Chrome based browsers
  • As of Google Chrome version 140, no configuration is necessary for Wayland ○ For versions prior to 140 and other Chrome based browsers that aren’t updated, setting the ozone-platform-hint is necessary. Go to chrome://flags in a tab, search for ozone-platform-hint and change the setting to “auto”. Restart the browser.
• Gaming is working well but we expect to need more fixes in our xwayland implementation for the Release Candidate.
  • Some games may start partially off screen. Press F11 or Super+F11 to full screen the game (Goat Simulator is one example)
• Display toggle hotkeys and an on-screen-display is not supported yet.
• The “Accent hint” around windows doesn’t match the roundness style setting in Appearance. This is expected for at least COSMIC apps for the Release Candidate.
• COSMIC has a built-in screenshot tool. If you require annotations, we recommend Flameshot which can be installed from Flathub via COSMIC Store. Version 13.1 or higher is required for COSMIC.
• COSMIC Store doesn’t currently display Flatpak suggested addons for apps. This is planned for the Release Candidate.
• Accessibility: The screen reader may not read all COSMIC apps widgets or may read them in an unintuitive direction. We’re working on screen reader flow and navigation for the Release Candidate.
• Some application indicators do not appear in the Notification Tray applet.
• Switching to an application using its application indicator does not currently work.
• Printing support in COSMIC Text Editor is planned for the release candidate
• Additional features and bugs expected to be fixed are triaged in the RC column on the project board

See more on the System76 website.