Stereo KWin root file system for the VKMS bench (2026-10-12, refreshed with KWin +stereo3d18.2)

A ready root file system with Stereo KWin for the vkms-stereo-bench's kwin phase
(https://github.com/Sparky-OS/sparky-stereo-os/tree/main/tools/vkms-stereo-bench),
so you can test without building the stereo stack yourself.

What is inside: Debian testing with Sparky Stereo OS's stereo packages pinned above Debian's:
- Stereo KWin 4:6.7.4-2+stereo3d18.2, with the DisplayXR window-geometry publisher
  (displayxr-window-geometry-publisher-kwin: geometry, placement, the drag table,
  move sync, buffer_device and capture exclusion);
- libkscreen and kscreen-doctor 4:6.7.4-1+stereo3d6;
- Qt 6.11.2+stereo3d5, Wayland client included;
- Mesa 26.1.6-1+stereo3d9;
- Xwayland +stereo3d1 and KIO +stereo3d1.
It also has D-Bus, gcc, pkg-config, wayland-scanner, wayland-protocols, and the Wayland,
EGL and GL development files the test clients need. The full list is
sparky-stereo-kwin-root-20261012.packages.

Use:
  mkdir sparky-root
  tar -C sparky-root --exclude='./dev/*' -xf sparky-stereo-kwin-root-20261012.tar.zst
  ./bench ... --kwin-root sparky-root run kwin
The bench's guest mounts its own /dev, so the device nodes are left out.

Checked before publishing: the root imported into Docker, KWin run as an ordinary user
with the SYS_NICE capability (kwin_wayland carries CAP_SYS_NICE as a file capability):
- Stereo KWin starts headless (virtual backend) and exits cleanly;
- kscreen-doctor lists its output;
- the DisplayXR publisher owns org.displayxr.WindowGeometry, and its placement
  capabilities read 27.

No 3D screen at hand? Stereo KWin's anaglyph output shows the same full side-by-side
picture on any ordinary monitor with red and cyan glasses.

Build it yourself: tools/vkms-stereo-bench/tools/build-kwin-root.sh (mmdebstrap, no root needed).

Sources: sparky-stereo-kwin-root-20261012-sources.tar holds the complete Debian source
packages of every modified package in this root: kwin, libkscreen, mesa, qt6-base,
xwayland, kf6-kio and base-files. Every other package is Debian's own, with its source in
Debian's archive. Each package keeps its own licence (GPL, LGPL, MIT and others, as
recorded in its debian/copyright).

The stereo changes live in our forks, for example
https://invent.kde.org/danielcamposramos/kwin/-/tree/stereo3d

Sparky Stereo OS, Daniel Ramos's edition of SparkyLinux (by Pawel "pavroo" Pijanowski).