Add a verified SteamOS ARM64 desktop and terminal experiment

THIRD_PARTY_NOTICES.md

@@ -46,4 +46,24 @@ Debian and Arch Linux ARM packages and additional Alpine packages are downloaded
 
 ## Source availability
 
+The optional local SteamFrame image experiment preserves SteamOS and its
+packages under their respective terms; the image is not included in the IPA.
+Device preparation adds Arch Linux ARM x11vnc 0.9.17 and libvncserver 0.9.15
+(GPL-2.0-family terms, with per-file notices). Their upstream sources are
+https://github.com/LibVNC/x11vnc/tree/0.9.17 and
+https://github.com/LibVNC/libvncserver/tree/LibVNCServer-0.9.15.
+The exact package hashes and helper build steps are retained in
+`tools/steamos/prepare-device-image.py`. LinuxRunner's added guest helper
+sources remain in `app/LinuxRunner/GUISupport.bundle`. Preserve component
+notices and corresponding source when sharing any prepared guest image.
+
+The optional SteamOS graphics overlay contains a separate Mesa build at
+`590bf21d918c86908d96d1f4590ecd25b9657171`, from
+https://gitlab.freedesktop.org/mesa/mesa.git. It retains Mesa's license inventory
+under `/opt/linuxrunner/steamos-gpu/share/licenses/mesa`, and its build identity
+in `BUILD.json`. The graphics probe's source and repository licensing files
+are included under `share/linuxrunner`. Packaging is defined by
+`tools/steamos/package-gpu-overlay.py`; the source/build options and isolated
+prefix are described in `docs/STEAMOS_EXPERIMENT.md`.
+
 The application source, build scripts and dependency revisions are retained in the repository. [SOURCE_ORIGIN.txt](SOURCE_ORIGIN.txt) records the release lineage and exact dependency commits. Submodule contents are not included in GitHub's automatic source archives; initialize the pinned submodules when building from a clone. Source-distribution requirements for bundled binaries apply separately from the licenses of packages downloaded later by users. The release source asset must include the matching application snapshot, pinned build dependencies, graphics source/patches, matching Alpine recipes and checksum-verified inputs, and matching Ghostty Web/Ghostty source. The unchanged bundled Alpine root archive can use the already retained matching source inputs. Preserve the complete notices asset alongside the IPA.

app/App.xcconfig

@@ -1,12 +1,14 @@
 #include "iOS.xcconfig"
 
 PRODUCT_NAME = LinuxKit
+LINUXRUNNER_DISPLAY_NAME = $(PRODUCT_NAME)
 PRODUCT_BUNDLE_IDENTIFIER = $(PRODUCT_BUNDLE_IDENTIFIER)
 INFOPLIST_FILE = app/Info.plist
 INFOPLIST_PREPROCESS = YES
 INFOPLIST_PREFIX_HEADER = $(BUILT_PRODUCTS_DIR)/infoplisticons.h
 ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon
-CODE_SIGN_ENTITLEMENTS = app/iSH.entitlements
+LINUXRUNNER_CODE_SIGN_ENTITLEMENTS = app/iSH.entitlements
+CODE_SIGN_ENTITLEMENTS = $(LINUXRUNNER_CODE_SIGN_ENTITLEMENTS)
 
 HEADER_SEARCH_PATHS = $(inherited) $(SRCROOT) $(SRCROOT)/deps/libarchive/libarchive
 // AccessibilityFixes.m contains a static constructor that we don't want removed

app/AppDelegate.m

@@ -291,7 +291,7 @@ - (int)boot {
     NSArray<NSString *> *command;
     command = UserPreferences.shared.bootCommand;
 #ifdef LINUXRUNNER
-    if ([LRRuntimeBridge activeEnvironmentIsDebian] || [LRRuntimeBridge activeEnvironmentIsArch]) command = @[@"/bin/sh", @"/usr/lib/linuxrunner/init.sh"];
+    if ([LRRuntimeBridge activeEnvironmentIsDebian] || [LRRuntimeBridge activeEnvironmentIsArch] || [LRRuntimeBridge activeEnvironmentIsSteamOS]) command = @[@"/bin/sh", @"/usr/lib/linuxrunner/init.sh"];
 #endif
     if (command.count == 0) {
         NSLog(@"boot command is empty");

app/Info.plist

@@ -5,7 +5,7 @@
 	<key>CFBundleDevelopmentRegion</key>
 	<string>$(DEVELOPMENT_LANGUAGE)</string>
 	<key>CFBundleDisplayName</key>
-	<string>$(PRODUCT_NAME)</string>
+	<string>$(LINUXRUNNER_DISPLAY_NAME)</string>
 	<key>CFBundleExecutable</key>
 	<string>$(EXECUTABLE_NAME)</string>
 	<key>CFBundleIdentifier</key>

app/LinuxRunner/GUISupport.bundle/desktop-components.sh

@@ -57,6 +57,39 @@ if [ "$environment" = plasma ]; then
  # password prompt over the desktop after a few idle minutes. First start of an
  # account only; a kscreenlockerrc the user already has is left as it is.
  plasma_config="${XDG_CONFIG_HOME:-$HOME/.config}"
+ if [ "$(sed -n 's/^ID=//p' /etc/os-release | tr -d '\"')" = steamos ]; then
+  export KWIN_COMPOSE=N
+  if [ "${LR_STEAMOS_GPU:-0}" = 1 ]; then
+   unset QT_QUICK_BACKEND QT_OPENGL LIBGL_ALWAYS_SOFTWARE
+   export QT_XCB_GL_INTEGRATION=xcb_egl QSG_RHI_BACKEND=opengl QSG_RHI_GL_USE_GLES=1
+  else
+   export QT_XCB_GL_INTEGRATION=none QT_QUICK_BACKEND=software QT_OPENGL=software
+  fi
+  mkdir -p "$plasma_config/autostart"
+  /bin/sh ./steamos-fonts.sh || echo 'STEAMOS_FONTS: optional default unavailable; desktop startup continues'
+  if [ ! -e "$plasma_config/startkderc" ] && [ ! -L "$plasma_config/startkderc" ]; then
+   printf '[General]\nsystemdBoot=false\n' > "$plasma_config/startkderc"
+  fi
+  if [ ! -e "$plasma_config/autostart/steam.desktop" ] && [ ! -L "$plasma_config/autostart/steam.desktop" ]; then
+   printf '[Desktop Entry]\nType=Application\nHidden=true\n' > "$plasma_config/autostart/steam.desktop"
+  fi
+  # The milestone is a desktop and terminal, without system services or updates.
+  # Discover's Flatpak notifier crashes; Baloo reserves a 256 GiB index mapping;
+  # the image's Python firewall/IBus applets also fail and consume address space.
+  # XDG overrides apply to existing accounts too, preserving explicit choices.
+  # iPadOS owns power, display brightness and authentication; their Linux
+  # agents repeatedly query a system bus that this userspace does not provide.
+  for applet in org.kde.discover.notifier baloo_file firewall-applet ibus powerdevil polkit-kde-authentication-agent-1; do
+   if [ ! -e "$plasma_config/autostart/$applet.desktop" ] && [ ! -L "$plasma_config/autostart/$applet.desktop" ]; then
+    printf '[Desktop Entry]\nType=Application\nHidden=true\n' > "$plasma_config/autostart/$applet.desktop"
+   fi
+  done
+  # Tell KDE's Places model that indexing is disabled too. Merely suppressing
+  # the daemon leaves it trying to enumerate the unavailable tags:/ location.
+  if grep -qx 'Hidden=true' "$plasma_config/autostart/baloo_file.desktop" && command -v kwriteconfig6 >/dev/null; then
+   kwriteconfig6 --file baloofilerc --group 'Basic Settings' --key Indexing-Enabled false
+  fi
+ fi
  if mkdir -p "$plasma_config" && [ ! -e "$plasma_config/kscreenlockerrc" ]; then
   printf '[Daemon]\nAutolock=false\nLockOnResume=false\n' > "$plasma_config/kscreenlockerrc" && echo 'DESKTOP_STARTUP: plasma screen locker defaults written (autolock off; iOS locks the device)'
  fi

app/LinuxRunner/GUISupport.bundle/desktop-profile.sh

@@ -19,6 +19,7 @@ cd "$(dirname "$0")"
 . ./support-common.sh
 mode=${1:-check}
 distro=$(sed -n 's/^ID=//p' /etc/os-release 2>/dev/null | tr -d '"')
+if [ "$distro" = steamos ]; then exec /bin/sh ./steamos-profile.sh "$@"; fi
 have() { command -v "$1" >/dev/null 2>&1; }
 helper_key() { { cat support-version; sha256sum "$@"; } | sha256sum | awk '{print $1}'; }
 

app/LinuxRunner/GUISupport.bundle/package-manager.sh

@@ -23,6 +23,11 @@ if command -v apt-get >/dev/null; then distro=debian
 elif command -v pacman >/dev/null; then distro=archarm
 elif command -v apk >/dev/null; then distro=alpine
 else echo 'PACKAGE_OPERATION: unsupported distribution'; exit 2; fi
+if [ "$(sed -n 's/^ID=//p' /etc/os-release | tr -d '\"')" = steamos ]; then
+ case "$operation" in installed|details|diagnose|dependencies) ;;
+  *) echo 'PACKAGE_OPERATION: The SteamOS image experiment supports installed-package inspection. Package changes and repository updates are not enabled for this prepared image.'; exit 2;;
+ esac
+fi
 printf 'operation=%s\ndistribution=%s\nstarted=%s\n' "$operation" "$distro" "$(date +%s)" > package-interrupted
 printf 'running\n' > package-result
 rm -f package-state.tsv.new package-details.txt.new

app/LinuxRunner/GUISupport.bundle/session.sh

@@ -57,7 +57,24 @@ if [ "$(id -u)" = 0 ] && [ "$guest_user" != root ]; then
         [ -c /dev/dri/card1 ] || mknod -m 660 /dev/dri/card1 c 226 1
         if (exec 3<>/dev/dri/card1) 2>/dev/null; then kms_desktop=wayfire-gpu; else rm -f /dev/dri/card1; fi
     fi
-    if [ "$mode" = desktop ] && { [ "$kms_desktop" = hyprland ] || [ "$kms_desktop" = wayfire-gpu ]; } && command -v seatd >/dev/null; then
+    if [ "$mode" = desktop ] && [ "$kms_desktop" = plasma ] &&
+        [ "$(sed -n 's/^ID=//p' /etc/os-release | tr -d '\"')" = steamos ]; then
+        /bin/sh ./steamos-desktop.sh tags-policy "$guest_user" || echo 'STEAMOS_TAGS: optional workaround unavailable; custom paths preserved, desktop startup continues'
+        rm -f /dev/dri/card0 /dev/dri/renderD128
+        mkdir -p /dev/dri
+        [ -c /dev/dri/card1 ] || mknod -m 660 /dev/dri/card1 c 226 1
+        [ -c /dev/dri/renderD129 ] || mknod -m 660 /dev/dri/renderD129 c 226 129
+        if (exec 3<>/dev/dri/card1) 2>/dev/null && [ -x /usr/lib/Xorg ] &&
+            /bin/sh ./steamos-gpu.sh; then
+            chown "root:$gid" /dev/dri/card1 /dev/dri/renderD129
+            chmod 660 /dev/dri/card1 /dev/dri/renderD129
+            printf 'enabled\n' > "$session/steamos-gpu"
+            echo 'GUI_SESSION: SteamOS gpu=virgl-metal (Xorg glamor and Qt; KWin effects off)'
+        else
+            rm -f /dev/dri/card1 /dev/dri/renderD129
+            echo 'GUI_SESSION: SteamOS gpu=software (GPU device or overlay unavailable)'
+        fi
+    elif [ "$mode" = desktop ] && { [ "$kms_desktop" = hyprland ] || [ "$kms_desktop" = wayfire-gpu ]; } && command -v seatd >/dev/null; then
         mkdir -p /dev/dri /run/udev/data
         [ -c /dev/dri/card0 ] || mknod -m 660 /dev/dri/card0 c 226 0
         [ -c /dev/dri/renderD128 ] || mknod -m 666 /dev/dri/renderD128 c 226 128
@@ -166,6 +183,11 @@ export DISPLAY=:$display
 # Debian Mesa needs server GLX for real desktop OpenGL contexts. This is
 # software rendering, independent of optional Metal framebuffer presentation.
 distro=$(sed -n 's/^ID=//p' /etc/os-release | tr -d '"')
+if [ "$distro" = steamos ]; then
+    # Breeze's QWidget painter crashed in the supplied image. Fusion keeps
+    # both direct children and D-Bus-activated Qt applications on one style.
+    export QT_STYLE_OVERRIDE=Fusion
+fi
 # Session graphics default chosen in Settings; a launcher's own
 # LR_GUI_GPU_MODE (command.sh) takes precedence for that application.
 gpu_mode=mesa
@@ -177,6 +199,15 @@ desktop_environment=linuxrunner
 [ ! -f "$session/desktop-environment" ] || desktop_environment=$(cat "$session/desktop-environment")
 case "$desktop_environment" in linuxrunner|plasma|lxqt|enlightenment|wayfire|hyprland) ;; *) desktop_environment=linuxrunner;; esac
 export LR_DESKTOP_ENVIRONMENT="$desktop_environment"
+steamos_gpu=0
+if [ "$distro" = steamos ] && [ "$mode" = desktop ] && [ "$desktop_environment" = plasma ] &&
+    [ "$(cat "$session/steamos-gpu" 2>/dev/null || true)" = enabled ] && [ -c /dev/dri/card1 ]; then
+    steamos_gpu=1
+    export LD_LIBRARY_PATH=/opt/linuxrunner/steamos-gpu/lib
+    export LIBGL_DRIVERS_PATH=/opt/linuxrunner/steamos-gpu/lib/dri
+    export __EGL_VENDOR_LIBRARY_FILENAMES=/opt/linuxrunner/steamos-gpu/share/glvnd/egl_vendor.d/50_mesa.json
+    export MESA_LOADER_DRIVER_OVERRIDE=virtio_gpu GALLIUM_DRIVER=virgl LR_STEAMOS_GPU=1
+fi
 glx_mode=off
 [ "$distro" != debian ] || glx_mode=software
 [ ! -f "$session/glx-mode" ] || glx_mode=$(cat "$session/glx-mode")
@@ -204,6 +235,17 @@ export QT_QPA_PLATFORM=${QT_QPA_PLATFORM:-xcb}
 export QT_FORCE_STDERR_LOGGING=${QT_FORCE_STDERR_LOGGING:-1}
 export QT_WIDGETS_RHI=${QT_WIDGETS_RHI:-0} QT_QUICK_BACKEND=${QT_QUICK_BACKEND:-software}
 export QT_OPENGL=${QT_OPENGL:-software} LIBGL_ALWAYS_SOFTWARE=${LIBGL_ALWAYS_SOFTWARE:-1}
+if [ "$steamos_gpu" = 1 ]; then
+    unset LIBGL_ALWAYS_SOFTWARE QT_QUICK_BACKEND QT_OPENGL
+    export QT_XCB_GL_INTEGRATION=xcb_egl QSG_RHI_BACKEND=opengl QSG_RHI_GL_USE_GLES=1 QSG_INFO=1
+fi
+steamos_software_fallback() {
+    steamos_gpu=0
+    unset LD_LIBRARY_PATH LIBGL_DRIVERS_PATH __EGL_VENDOR_LIBRARY_FILENAMES MESA_LOADER_DRIVER_OVERRIDE GALLIUM_DRIVER LR_STEAMOS_GPU
+    unset QSG_RHI_BACKEND QSG_RHI_GL_USE_GLES QSG_INFO
+    export QT_QUICK_BACKEND=software QT_OPENGL=software LIBGL_ALWAYS_SOFTWARE=1 QT_XCB_GL_INTEGRATION=none
+    echo 'GUI_SESSION: SteamOS GPU check failed; starting the software desktop (see graphics.log and xorg.log)'
+}
 # A fresh X server belongs to this guest root; DISPLAY is session-scoped.
 width=640 height=480
 if [ -f "$session/geometry" ]; then
@@ -213,12 +255,24 @@ if [ -f "$session/geometry" ]; then
     width=${geometry%x*};height=${geometry#*x}
     if [ "$width" -lt 320 ] || [ "$width" -gt 2560 ] || [ "$height" -lt 240 ] || [ "$height" -gt 1600 ] || [ $((width % 2)) -ne 0 ] || [ $((height % 2)) -ne 0 ]; then echo 'GUI_SESSION: invalid display geometry'; exit 2; fi
 fi
+if [ "$steamos_gpu" = 1 ] && ! /opt/linuxrunner/steamos-gpu/bin/graphics-check > "$session/graphics.log" 2>&1; then
+    steamos_software_fallback
+fi
 export XAUTHORITY="$session/authority"
 umask 077
 xauth -f "$XAUTHORITY" add "$DISPLAY" . "$(cat "$session/cookie")"
-echo "GUI_SESSION: root=${LINUXRUNNER_ENVIRONMENT:-current} distribution=$distro DISPLAY=$DISPLAY geometry=${width}x${height} backend=xvfb-rfb interpreter-baseline"
-echo "GUI_SESSION: starting X.Org software display, ${width}x${height}, no JIT"
-Xvfb "$DISPLAY" -screen 0 "${width}x${height}x24" -nolisten tcp -auth "$XAUTHORITY" "$shm_switch" MIT-SHM "$glx_switch" GLX > "$session/xvfb.log" 2>&1 & xpid=$!
+echo "GUI_SESSION: root=${LINUXRUNNER_ENVIRONMENT:-current} distribution=$distro DISPLAY=$DISPLAY geometry=${width}x${height} backend=$([ "$steamos_gpu" = 1 ] && echo xorg-virgl-rfb || echo xvfb-rfb) interpreter-baseline"
+if [ "$steamos_gpu" = 1 ]; then
+    cp ./steamos-xorg.conf "$session/xorg.conf"
+    echo 'xorg-virgl' > "$session/display-backend"
+    echo "GUI_SESSION: starting Xorg modesetting/glamor on virgl/Metal, ${width}x${height}, no JIT"
+    /usr/lib/Xorg "$DISPLAY" -config "$session/xorg.conf" -logfile "$session/xorg.log" -noreset -nolisten tcp \
+        -novtswitch -sharevts -auth "$XAUTHORITY" > "$session/xvfb.log" 2>&1 & xpid=$!
+else
+    echo 'xvfb-software' > "$session/display-backend"
+    echo "GUI_SESSION: starting X.Org software display, ${width}x${height}, no JIT"
+    Xvfb "$DISPLAY" -screen 0 "${width}x${height}x24" -nolisten tcp -auth "$XAUTHORITY" "$shm_switch" MIT-SHM "$glx_switch" GLX > "$session/xvfb.log" 2>&1 & xpid=$!
+fi
 i=0
 while [ ! -S "/tmp/.X11-unix/X$display" ]; do
     [ ! -f "$session/stop" ] || exit 0
@@ -245,7 +299,7 @@ xmodmap -pm >> "$session/keymap.log" 2>&1 || true
 xkb=-xkb
 if [ -f "$session/xkb-mode" ] && [ "$(cat "$session/xkb-mode")" = noxkb ]; then xkb=-noxkb; fi
 focus_policy=managed; [ "$mode" != desktop ] || focus_policy=window-manager
-echo "GUI_SESSION: keyboard=$xkb focus=$focus_policy encoding=Hextile/Raw software-rendering"
+echo "GUI_SESSION: keyboard=$xkb focus=$focus_policy encoding=Hextile/Raw renderer=$([ "$steamos_gpu" = 1 ] && echo virgl-metal || echo software)"
 # A Linux sockaddr_un path holds at most 107 bytes. A support-directory UUID
 # path plus GVFS/Qt socket suffix exceeds it. Use a uniquely owned short path
 # for every GUI mode, with restrictive permissions and no preexisting reuse.
@@ -271,6 +325,11 @@ if command -v dbus-daemon >/dev/null; then
             if dbus-update-activation-environment DISPLAY XAUTHORITY XDG_RUNTIME_DIR HOME PATH DBUS_SESSION_BUS_ADDRESS; then
                 echo 'GUI_SESSION: dbus_activation_environment=PASS (explicit session variables, no systemd required)'
             else echo 'GUI_SESSION: dbus_activation_environment=FAIL; inspect bus.log'; fi
+            if [ "$steamos_gpu" = 1 ]; then
+                dbus-update-activation-environment LD_LIBRARY_PATH LIBGL_DRIVERS_PATH __EGL_VENDOR_LIBRARY_FILENAMES \
+                    MESA_LOADER_DRIVER_OVERRIDE GALLIUM_DRIVER LR_STEAMOS_GPU QT_STYLE_OVERRIDE \
+                    QT_XCB_GL_INTEGRATION QSG_RHI_BACKEND QSG_RHI_GL_USE_GLES || true
+            fi
         fi;;
         *) echo 'GUI_SESSION: dbus_session=unavailable; inspect bus.log (applications still attempted)';;
     esac
@@ -313,7 +372,9 @@ echo "GUI_INPUT: mode=$input_mode experimental=$([ "$input_mode" = eager ] && ec
 # autocomplete splice typed URLs (2 of 5 gate runs), so it stays opt-in.
 # The others are latency experiments.
 vnc_timing=default
+[ "$steamos_gpu" != 1 ] || vnc_timing=adaptive
 [ ! -f "$session/vnc-timing" ] || vnc_timing=$(cat "$session/vnc-timing")
+if [ "$vnc_timing" = default ] && [ "$steamos_gpu" = 1 ]; then vnc_timing=adaptive; fi
 case "$vnc_timing" in
  default|legacy) vnc_timing_options="-noxdamage -defer 16 -wait 25";;
  threads) vnc_timing_options="-noxdamage -defer 16 -wait 25 -threads";;

app/LinuxRunner/GUISupport.bundle/steamos-desktop.sh

@@ -0,0 +1,42 @@
+#!/bin/sh
+# Reversible SteamOS-only workaround for KIO 6.14 enumerating tags even when
+# Baloo is disabled. Retain the original plugin outside Qt's plugin search tree.
+set -eu
+[ "$(id -u)" = 0 ] || { echo 'STEAMOS_TAGS: root-required'; exit 1; }
+[ "$(sed -n 's/^ID=//p' /etc/os-release | tr -d '\"')" = steamos ] || exit 0
+plugin=/usr/lib/qt6/plugins/kf6/kio/tags.so
+backup=/opt/linuxrunner/steamos-disabled-plugins
+action=${1:-}
+case "$action" in
+ tags-policy)
+  user=${2:-}
+  case "$user" in ''|*[!a-z0-9_-]*|[0-9-]*) exit 2;; esac
+  home=$(awk -F: -v name="$user" '$1==name {print $6; count++} END {if(count!=1)exit 1}' /etc/passwd)
+  case "$home" in /*) ;; *) exit 2;; esac
+  # No override means the managed desktop's default (Baloo off). Preserve an
+  # explicit account autostart override and put back our saved worker for it.
+  override="$home/.config/autostart/baloo_file.desktop"
+  action=disable-tags
+  if [ -e "$override" ] || [ -L "$override" ]; then
+   grep -qx 'Hidden=true' "$override" || action=restore-tags
+  fi
+  ;;
+ disable-tags|restore-tags) ;;
+ *) echo 'Usage: steamos-desktop.sh tags-policy USER | disable-tags | restore-tags'; exit 2;;
+esac
+for path in /opt /opt/linuxrunner "$backup" "$plugin" "$backup/tags.so"; do
+ [ ! -L "$path" ] || { echo 'STEAMOS_TAGS: symlink refused'; exit 1; }
+done
+if [ "$action" = disable-tags ]; then
+ if [ -f "$plugin" ]; then
+  mkdir -p "$backup"
+  # An unexpected second copy can be a package update; keep both untouched.
+  [ ! -e "$backup/tags.so" ] || { echo 'STEAMOS_TAGS: plugin changed; retained copies, no override'; exit 0; }
+  mv "$plugin" "$backup/tags.so"
+ fi
+ [ ! -f "$backup/tags.so" ] || echo 'STEAMOS_TAGS: unavailable worker disabled; original retained (restore-tags to undo)'
+elif [ -f "$backup/tags.so" ]; then
+ [ ! -e "$plugin" ] || { echo 'STEAMOS_TAGS: package worker already present; backup retained'; exit 0; }
+ mv "$backup/tags.so" "$plugin"
+ echo 'STEAMOS_TAGS: original worker restored'
+fi

app/LinuxRunner/GUISupport.bundle/steamos-fonts.sh

@@ -0,0 +1,27 @@
+#!/bin/sh
+# Managed default for a scaled virtual display, run as the selected Linux user.
+# RGB subpixel antialiasing assumes a fixed physical RGB stripe arrangement;
+# it produces colored edges when the framebuffer is resized or rotated.
+set -eu
+config=${XDG_CONFIG_HOME:-$HOME/.config}
+file="$config/kdeglobals"
+if [ -L "$file" ] || { [ -e "$file" ] && [ ! -f "$file" ]; }; then
+    echo 'STEAMOS_FONTS: custom configuration path preserved'
+    exit 0
+fi
+# KConfig handles the write. Conservatively preserve any explicit account key,
+# including immutable/expanded forms, even when it is in another group.
+if [ -f "$file" ] && grep -Eq '^[[:space:]]*XftSubPixel(\[\$[ie]\])*[[:space:]]*=' "$file"; then
+    echo 'STEAMOS_FONTS: explicit subpixel preference preserved'
+    exit 0
+fi
+if ! command -v kwriteconfig6 >/dev/null; then
+    echo 'STEAMOS_FONTS: configuration tool unavailable; defaults unchanged'
+    exit 0
+fi
+mkdir -p "$config" || { echo 'STEAMOS_FONTS: configuration directory unavailable; defaults unchanged'; exit 0; }
+if kwriteconfig6 --file "$file" --group General --key XftSubPixel none; then
+    echo 'STEAMOS_FONTS: grayscale antialiasing default for scaled framebuffer'
+else
+    echo 'STEAMOS_FONTS: configuration write unavailable; defaults unchanged'
+fi