diff --git a/.gitignore b/.gitignore
index c888b21..9ed1d40 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,12 @@
 /target-android
 Cargo.lock.bak
 *.log
+
+# makepkg build products. `packaging/PKGBUILD` and the .desktop entry are
+# sources and belong in the tree; everything makepkg derives from them does
+# not — `pkg/` and `src/` are staging directories it recreates on every run,
+# and the package itself is 33 MB of compiled output.
+/packaging/pkg/
+/packaging/src/
+/packaging/*.pkg.tar.*
+/packaging/*.log
diff --git a/packaging/PKGBUILD b/packaging/PKGBUILD
new file mode 100644
index 0000000..5b29c8f
--- /dev/null
+++ b/packaging/PKGBUILD
@@ -0,0 +1,46 @@
+# Maintainer: Duncan Tourolle <duncan@tourolle.paris>
+#
+# Builds from the local checkout rather than a release tarball, which is what
+# makes `makepkg -si` in this directory install what you are actually working
+# on. Swap `source` for a tagged tarball when there is something to release.
+pkgname=darkroom
+pkgver=0.3.0
+pkgrel=1
+pkgdesc="Non-destructive RAW photo library and editor"
+arch=('x86_64')
+url="https://gitea.tourolle.paris/dtourolle/DarkRoom"
+license=('GPL-3.0-or-later')
+# Runtime: Vulkan for wgpu, and a Secret Service implementation for the
+# Nextcloud credentials (FR-NC-2) — gnome-keyring or kwallet both provide it.
+depends=('vulkan-icd-loader' 'fontconfig' 'libxkbcommon')
+makedepends=('cargo' 'git')
+optdepends=('gnome-keyring: store Nextcloud credentials'
+            'kwallet: store Nextcloud credentials')
+options=('!lto')  # the workspace sets its own LTO in Cargo.toml
+
+_repo="$(cd "${startdir}/.." && pwd)"
+
+build() {
+    cd "${_repo}"
+    export RUSTUP_TOOLCHAIN=stable
+    export CARGO_TARGET_DIR="${_repo}/target"
+    cargo build --release --locked -p darkroom-desktop
+}
+
+package() {
+    cd "${_repo}"
+    install -Dm755 "target/release/darkroom-desktop" \
+        "${pkgdir}/usr/bin/darkroom-desktop"
+
+    install -Dm644 "packaging/paris.tourolle.darkroom.desktop" \
+        "${pkgdir}/usr/share/applications/paris.tourolle.darkroom.desktop"
+
+    # The icon's *name* is the contract, not its path: the desktop entry says
+    # `Icon=paris.tourolle.darkroom` and the compositor resolves that through
+    # the hicolor theme. Installed under 256x256 because that is the source's
+    # actual size — lying about it makes scaled-down icons look wrong.
+    install -Dm644 "ui/dr-ui/ui/app-icon.png" \
+        "${pkgdir}/usr/share/icons/hicolor/256x256/apps/paris.tourolle.darkroom.png"
+
+    install -Dm644 "README.md" "${pkgdir}/usr/share/doc/${pkgname}/README.md"
+}
diff --git a/packaging/paris.tourolle.darkroom.desktop b/packaging/paris.tourolle.darkroom.desktop
new file mode 100644
index 0000000..7d18de6
--- /dev/null
+++ b/packaging/paris.tourolle.darkroom.desktop
@@ -0,0 +1,18 @@
+[Desktop Entry]
+Type=Application
+Name=DarkRoom
+GenericName=Photo Editor
+Comment=Non-destructive RAW photo library and editor
+# The basename of this file is the contract: a Wayland compositor finds it by
+# matching the surface's app_id, which `dr_ui::run` sets to the same string.
+# Rename one without the other and the icon silently disappears.
+Exec=darkroom-desktop %F
+Icon=paris.tourolle.darkroom
+Terminal=false
+Categories=Graphics;Photography;RasterGraphics;2DGraphics;
+Keywords=RAW;photo;photography;develop;darkroom;library;
+# X11 falls back to matching the WM_CLASS instead of the app_id; winit sets it
+# from the same string, so naming it here covers both display servers.
+StartupWMClass=paris.tourolle.darkroom
+StartupNotify=true
+MimeType=image/x-canon-cr2;image/x-canon-cr3;image/x-nikon-nef;image/x-sony-arw;image/x-adobe-dng;image/x-fuji-raf;image/x-olympus-orf;image/x-panasonic-rw2;image/jpeg;image/png;image/tiff;
diff --git a/ui/dr-ui/src/lib.rs b/ui/dr-ui/src/lib.rs
index 4463f42..e089b03 100644
--- a/ui/dr-ui/src/lib.rs
+++ b/ui/dr-ui/src/lib.rs
@@ -733,6 +733,30 @@ pub fn run(paths: Vec<PathBuf>) -> Result<()> {
     let entries = Rc::new(RefCell::new(collect(&paths)));
     log::info!("{} image(s) to browse", entries.borrow().len());
 
+    // TRACES: FR-PLAT-LIN-1
+    // The name the compositor knows this window by, and the reason the
+    // launcher shows a real icon rather than a grey square.
+    //
+    // `app.slint` sets `icon:`, and that is genuinely embedded (see
+    // `build.rs`) — but a Wayland compositor ignores a client-set icon
+    // entirely. It takes the icon from the `.desktop` file whose basename
+    // matches the surface's `app_id`, and nothing else. So the embedded icon
+    // is what X11 and the window itself use, and *this* is what GNOME's
+    // overview, dash and alt-tab use. Both are needed and neither substitutes
+    // for the other.
+    //
+    // The string must equal the installed `.desktop` file's basename exactly:
+    // `packaging/paris.tourolle.darkroom.desktop`. It matches the Android
+    // package id (`AndroidManifest.xml`) on purpose — one application, one
+    // reverse-DNS name on both platforms.
+    //
+    // Before the window, necessarily: it is read when the surface is created.
+    if let Err(e) = slint::set_xdg_app_id("paris.tourolle.darkroom") {
+        // Not fatal. On X11 and on Android this does nothing useful, and a
+        // missing app id costs an icon rather than a working application.
+        log::debug!("could not set the xdg app id: {e}");
+    }
+
     // Before the window, and it has to be: this selects the Slint backend, and
     // creating a window selects one for us. See `shared_gpu`. The device is
     // shared by demosaic, the adjust pass and the compositor; without one the