/ bench — unproven

Steam Machine test bench.

Nothing here has run on the hardware yet. Copy a command, try it on the machine, mark what happened. Results live in this browser only — hit export when you want them out.

0/13 recorded0 works0 broken

Probe

3 tests

Establish what the box actually is before trusting any result below.

01
SteamOS build & kernel
unknown
Which SteamOS release and kernel does the Steam Machine ship, and does it differ from Deck 3.x?
pass looks like
VERSION_ID and BUILD_ID from os-release; record them — every other result on this page is only valid for this build.
```
cat /etc/os-release
```
```
uname -srm
```
```
hostnamectl | sed -n "1,12p"
```
Chassis / hardware vendor line tells us how the machine self-identifies.
02
Session & compositor
unknown
Is the desktop session the same Plasma/gamescope pairing as the Deck, and is it Wayland-only?
pass looks like
XDG_CURRENT_DESKTOP=KDE, XDG_SESSION_TYPE=wayland, and a running gamescope process in Game Mode.
```
echo "desktop=$XDG_CURRENT_DESKTOP session=$XDG_SESSION_TYPE"
```
```
pgrep -a gamescope | head -3
```
```
plasmashell --version
```
03
Read-only rootfs
low risk
unknown
Is / still immutable? Anything that writes outside $HOME needs this answered first.
pass looks like
"enabled" — themes must then live under ~/ (which survives updates) and never in /usr.
```
sudo steamos-readonly status
```
```
findmnt -no FSTYPE,OPTIONS / /home
```
Confirms the btrfs/ext4 split and which mount is writable.

Theming

10 tests

Does the Deck theming stack — CSS Loader, Plasma, boot video — transfer to the Steam Machine untouched?

01
Decky Loader service
unknown
Does Decky Loader install and stay running on this build? CSS Loader is a Decky plugin, so everything downstream depends on it.
pass looks like
plugin_loader.service active (running), and ~/homebrew/plugins exists.
```
systemctl status plugin_loader --no-pager | sed -n "1,6p"
```
```
ls -1 ~/homebrew/plugins 2>/dev/null || echo "no decky plugins dir"
```
02
CSS Loader installer
low risk
unknown
Does the upstream installer's Deck assumptions (paths, service restart) hold on Steam Machine?
pass looks like
Installer exits 0, plugin appears in the Decky menu in Game Mode, no restart loop in the service log.
```
curl -L https://github.com/suchmememanyskill/SDH-CssLoader/raw/main/install_release.sh | sh
```
External script — read it once before piping if you have not already.
```
journalctl -u plugin_loader -n 20 --no-pager
```
undo
```
rm -rf ~/homebrew/plugins/SDH-CssLoader && sudo systemctl restart plugin_loader.service
```

Hand-rolled theme + manifest version

low risk

unknown: Which CSS Loader manifest_version does this build accept? Writing a minimal theme by hand isolates that from any store download.
pass looks like: "magus test" shows up in the CSS Loader plugin list and the Quick Access panel picks up the accent colour.

mkdir -p ~/homebrew/themes/magus-test && cat > ~/homebrew/themes/magus-test/theme.json <<'JSON'
{
  "name": "magus test",
  "version": "v1.0",
  "author": "magus.sh",
  "manifest_version": 8,
  "inject": { "shared.css": ["QuickAccess", "SP", "Desktop"] }
}
JSON

Bump manifest_version and re-run if the plugin rejects it — that number is the actual thing under test.

cat > ~/homebrew/themes/magus-test/shared.css <<'CSS'
:root { --magus-probe: #7aa2f7; }
body { outline: 2px solid var(--magus-probe); outline-offset: -2px; }
CSS

A visible outline is a blunt but unmistakable "the CSS landed" signal.

sudo systemctl restart plugin_loader.service

undo

rm -rf ~/homebrew/themes/magus-test && sudo systemctl restart plugin_loader.service

04
Plasma colour scheme
desktop mode
unknown
Do the plasma-apply-* CLI tools exist on this image, or has Valve trimmed them?
pass looks like
A scheme list prints, and applying one repaints the desktop session immediately.
```
plasma-apply-colorscheme --list-schemes
```
```
plasma-apply-colorscheme BreezeDark
```
undo
```
plasma-apply-colorscheme BreezeDark
```
05
Global (look-and-feel) theme
desktop modemedium risk
unknown
Does lookandfeeltool survive here, and does applying a global theme break the Return-to-Game-Mode shortcut?
pass looks like
Theme list prints; after applying, the Return to Gaming Mode desktop icon still works.
```
lookandfeeltool -l
```
```
lookandfeeltool -a org.kde.breezedark.desktop
```
undo
```
lookandfeeltool -a org.kde.breezedark.desktop
```
06
Cursor, icon & desktop theme
desktop mode
unknown
Are the Steam-branded cursor and icon themes present, and do Wayland clients pick up a change without a relog?
pass looks like
Each --list-themes prints; the cursor changes without logging out.
```
plasma-apply-cursortheme --list-themes
```
```
plasma-apply-desktoptheme --list-themes
```
```
ls -1 /usr/share/icons ~/.local/share/icons 2>/dev/null
```
07
Flatpak apps following the system theme
desktop mode
unknown
Do Flatpaks read the host GTK theme once the config dirs are exposed, or do they stay Adwaita-light?
pass looks like
Overrides apply cleanly and a relaunched Flatpak (Brave, VLC) matches the desktop.
```
flatpak override --user --filesystem=xdg-config/gtk-3.0:ro --filesystem=xdg-config/gtk-4.0:ro
```
```
gsettings get org.gnome.desktop.interface color-scheme
```
```
flatpak override --user --show
```
undo
```
flatpak override --user --reset
```
08
Boot video override
low risk
unknown
Does the Steam Machine honour the Deck uioverrides/movies path for the startup animation?
pass looks like
Directory exists (or can be created) and a webm dropped in as deck_startup.webm plays on next boot.
```
mkdir -p ~/.steam/root/config/uioverrides/movies
```
```
ls -la ~/.steam/root/config/uioverrides/movies
```
```
ls -1 ~/.steam/root/steamui/movies 2>/dev/null | head
```
Stock animations — filenames here tell us what an override has to be called on this build.
undo
```
rm -f ~/.steam/root/config/uioverrides/movies/deck_startup.webm
```
09
Custom fonts
unknown
Do user fonts in ~/.local/share/fonts get picked up by both Plasma and the Steam client?
pass looks like
fc-cache sees the new font and it is selectable in Plasma settings; note whether Game Mode also picks it up.
```
mkdir -p ~/.local/share/fonts && fc-cache -fv ~/.local/share/fonts | tail -3
```
```
fc-list : family | sort -u | wc -l
```
undo
```
rm -rf ~/.local/share/fonts && fc-cache -f
```
10
Survives a SteamOS update
unknown
Which of the above live on the writable /home partition and therefore survive an OS update?
pass looks like
Everything under ~/homebrew, ~/.local, ~/.steam resolves inside /home — anything that does not will be wiped.
```
for p in ~/homebrew ~/.local/share/fonts ~/.steam/root/config/uioverrides ~/.config/kdeglobals; do printf "%-46s %s\n" "$p" "$(df --output=target "$p" 2>/dev/null | tail -1)"; done
```

Anything that passes here graduates to a card in/setup. Anything that breaks is worth a note on why — that's the part upstream docs never write down.

Probe

SteamOS build & kernel

Session & compositor

Read-only rootfs

Theming

Decky Loader service

CSS Loader installer

Hand-rolled theme + manifest version

Plasma colour scheme

Global (look-and-feel) theme

Cursor, icon & desktop theme

Flatpak apps following the system theme

Boot video override

Custom fonts

Survives a SteamOS update