diff --git a/cartridges/application.py b/cartridges/application.py
index 4e0543a..a5c4154 100644
--- a/cartridges/application.py
+++ b/cartridges/application.py
@@ -10,7 +10,7 @@ from gi.repository import Adw
 
 from cartridges import games
 from cartridges.games import Game
-from cartridges.sources import Source, SteamSource
+from cartridges.sources import Source, steam
 
 from .config import APP_ID, PREFIX
 from .ui.window import Window
@@ -29,7 +29,7 @@ class Application(Adw.Application):
         self.set_accels_for_action("app.quit", ("<Control>q",))
 
         saved = tuple(games.load())
-        new = self.import_games(SteamSource(), skip_ids={g.game_id for g in saved})
+        new = self.import_games(steam, skip_ids={g.game_id for g in saved})
         games.model.splice(0, 0, (*saved, *new))
 
     @staticmethod
diff --git a/cartridges/meson.build b/cartridges/meson.build
index 4a3f1e1..aa2fd8c 100644
--- a/cartridges/meson.build
+++ b/cartridges/meson.build
@@ -1,14 +1,10 @@
 python.install_sources(
-    files(
-        '__init__.py',
-        '__main__.py',
-        'application.py',
-        'games.py',
-        'sources.py',
-    ),
+    files('__init__.py', '__main__.py', 'application.py', 'games.py'),
     subdir: 'cartridges',
 )
 
+install_subdir('sources', install_dir: python.get_install_dir() / 'cartridges')
+
 configure_file(
     input: 'config.py.in',
     output: '@BASENAME@',
diff --git a/cartridges/sources.py b/cartridges/sources.py
deleted file mode 100644
index 743f745..0000000
--- a/cartridges/sources.py
+++ /dev/null
@@ -1,136 +0,0 @@
-# SPDX-License-Identifier: GPL-3.0-or-later
-# SPDX-FileCopyrightText: Copyright 2023 Geoffrey Coulaud
-# SPDX-FileCopyrightText: Copyright 2022-2025 kramo
-
-import itertools
-import os
-import re
-import sys
-import time
-from collections.abc import Generator, Iterable
-from pathlib import Path
-from typing import Protocol
-
-from gi.repository import Gdk, GLib
-
-from cartridges.games import Game
-
-DATA = Path(GLib.get_user_data_dir())
-FLATPAK = Path.home() / ".var" / "app"
-PROGRAM_FILES_X86 = Path(os.getenv("PROGRAMFILES(X86)", r"C:\Program Files (x86)"))
-APPLICATION_SUPPORT = Path.home() / "Library" / "Application Support"
-
-OPEN = (
-    "open"
-    if sys.platform.startswith("darwin")
-    else "start"
-    if sys.platform.startswith("win32")
-    else "xdg-open"
-)
-
-
-class Source(Protocol):
-    """A source of games to import."""
-
-    ID: str
-
-    def get_games(self, *, skip_ids: Iterable[str]) -> Generator[Game]:
-        """Installed games, except those in `skip_ids`."""
-        ...
-
-
-class SteamSource:
-    """A source for the Valve's Steam."""
-
-    ID: str = "steam"
-
-    _INSTALLED_MASK = 4
-    _CAPSULE_NAMES = "library_600x900.jpg", "library_capsule.jpg"
-    _DATA_PATHS = (
-        Path.home() / ".steam" / "steam",
-        DATA / "Steam",
-        FLATPAK / "com.valvesoftware.Steam" / "data" / "Steam",
-        PROGRAM_FILES_X86 / "Steam",
-        APPLICATION_SUPPORT / "Steam",
-    )
-
-    @property
-    def _data(self) -> Path:
-        for path in self._DATA_PATHS:
-            if path.is_dir():
-                return path
-
-        raise FileNotFoundError
-
-    @property
-    def _library_folders(self) -> Generator[Path]:
-        return (
-            steamapps
-            for folder in re.findall(
-                r'"path"\s+"(.*)"\n',
-                (self._data / "steamapps" / "libraryfolders.vdf").read_text("utf-8"),
-                re.IGNORECASE,
-            )
-            if (steamapps := Path(folder) / "steamapps").is_dir()
-        )
-
-    @property
-    def _manifests(self) -> Generator[Path]:
-        return (
-            manifest
-            for folder in self._library_folders
-            for manifest in folder.glob("appmanifest_*.acf")
-            if manifest.is_file()
-        )
-
-    def get_games(self, *, skip_ids: Iterable[str]) -> Generator[Game]:
-        """Installed Steam games."""
-        added = int(time.time())
-        librarycache = self._data / "appcache" / "librarycache"
-        appids = {i.rsplit("_", 1)[-1] for i in skip_ids if i.startswith(f"{self.ID}_")}
-        for manifest in self._manifests:
-            contents = manifest.read_text("utf-8")
-            try:
-                name, appid, stateflags = (
-                    self._parse(contents, key)
-                    for key in ("name", "appid", "stateflags")
-                )
-                stateflags = int(stateflags)
-            except ValueError:
-                continue
-
-            duplicate = appid in appids
-            installed = stateflags & self._INSTALLED_MASK
-
-            if duplicate or not installed:
-                continue
-
-            game = Game(
-                added=added,
-                executable=f"{OPEN} steam://rungameid/{appid}",
-                game_id=f"{self.ID}_{appid}",
-                source=self.ID,
-                name=name,
-            )
-
-            for path in itertools.chain.from_iterable(
-                (librarycache / appid).rglob(filename)
-                for filename in self._CAPSULE_NAMES
-            ):
-                try:
-                    game.cover = Gdk.Texture.new_from_filename(str(path))
-                except GLib.Error:
-                    continue
-                else:
-                    break
-
-            yield game
-            appids.add(appid)
-
-    @staticmethod
-    def _parse(manifest: str, key: str) -> str:
-        match = re.search(rf'"{key}"\s+"(.*)"\n', manifest, re.IGNORECASE)
-        if match and isinstance(group := match.group(1), str):
-            return group
-
-        raise ValueError
diff --git a/cartridges/sources/__init__.py b/cartridges/sources/__init__.py
new file mode 100644
index 0000000..8ef3a45
--- /dev/null
+++ b/cartridges/sources/__init__.py
@@ -0,0 +1,36 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+# SPDX-FileCopyrightText: Copyright 2025 kramo
+
+import os
+import sys
+from collections.abc import Generator, Iterable
+from pathlib import Path
+from typing import Protocol
+
+from gi.repository import GLib
+
+from cartridges.games import Game
+
+DATA = Path(GLib.get_user_data_dir())
+FLATPAK = Path.home() / ".var" / "app"
+PROGRAM_FILES_X86 = Path(os.getenv("PROGRAMFILES(X86)", r"C:\Program Files (x86)"))
+APPLICATION_SUPPORT = Path.home() / "Library" / "Application Support"
+
+OPEN = (
+    "open"
+    if sys.platform.startswith("darwin")
+    else "start"
+    if sys.platform.startswith("win32")
+    else "xdg-open"
+)
+
+
+class Source(Protocol):
+    """A source of games to import."""
+
+    ID: str
+
+    @staticmethod
+    def get_games(*, skip_ids: Iterable[str]) -> Generator[Game]:
+        """Installed games, except those in `skip_ids`."""
+        ...
diff --git a/cartridges/sources/steam.py b/cartridges/sources/steam.py
new file mode 100644
index 0000000..b647d66
--- /dev/null
+++ b/cartridges/sources/steam.py
@@ -0,0 +1,107 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+# SPDX-FileCopyrightText: Copyright 2023 Geoffrey Coulaud
+# SPDX-FileCopyrightText: Copyright 2022-2025 kramo
+
+import itertools
+import re
+import time
+from collections.abc import Generator, Iterable
+from pathlib import Path
+
+from gi.repository import Gdk, GLib
+
+from cartridges.games import Game
+
+from . import APPLICATION_SUPPORT, DATA, FLATPAK, OPEN, PROGRAM_FILES_X86
+
+ID: str = "steam"
+
+_INSTALLED_MASK = 4
+_CAPSULE_NAMES = "library_600x900.jpg", "library_capsule.jpg"
+_DATA_PATHS = (
+    Path.home() / ".steam" / "steam",
+    DATA / "Steam",
+    FLATPAK / "com.valvesoftware.Steam" / "data" / "Steam",
+    PROGRAM_FILES_X86 / "Steam",
+    APPLICATION_SUPPORT / "Steam",
+)
+
+
+def get_games(*, skip_ids: Iterable[str]) -> Generator[Game]:
+    """Installed Steam games."""
+    added = int(time.time())
+    librarycache = _data_dir() / "appcache" / "librarycache"
+    appids = {i.rsplit("_", 1)[-1] for i in skip_ids if i.startswith(f"{ID}_")}
+    for manifest in _manifests():
+        contents = manifest.read_text("utf-8")
+        try:
+            name, appid, stateflags = (
+                _parse(contents, key) for key in ("name", "appid", "stateflags")
+            )
+            stateflags = int(stateflags)
+        except ValueError:
+            continue
+
+        duplicate = appid in appids
+        installed = stateflags & _INSTALLED_MASK
+
+        if duplicate or not installed:
+            continue
+
+        game = Game(
+            added=added,
+            executable=f"{OPEN} steam://rungameid/{appid}",
+            game_id=f"{ID}_{appid}",
+            source=ID,
+            name=name,
+        )
+
+        for path in itertools.chain.from_iterable(
+            (librarycache / appid).rglob(filename) for filename in _CAPSULE_NAMES
+        ):
+            try:
+                game.cover = Gdk.Texture.new_from_filename(str(path))
+            except GLib.Error:
+                continue
+            else:
+                break
+
+        yield game
+        appids.add(appid)
+
+
+def _data_dir() -> Path:
+    for path in _DATA_PATHS:
+        if path.is_dir():
+            return path
+
+    raise FileNotFoundError
+
+
+def _library_folders() -> Generator[Path]:
+    return (
+        steamapps
+        for folder in re.findall(
+            r'"path"\s+"(.*)"\n',
+            (_data_dir() / "steamapps" / "libraryfolders.vdf").read_text("utf-8"),
+            re.IGNORECASE,
+        )
+        if (steamapps := Path(folder) / "steamapps").is_dir()
+    )
+
+
+def _manifests() -> Generator[Path]:
+    return (
+        manifest
+        for folder in _library_folders()
+        for manifest in folder.glob("appmanifest_*.acf")
+        if manifest.is_file()
+    )
+
+
+def _parse(manifest: str, key: str) -> str:
+    match = re.search(rf'"{key}"\s+"(.*)"\n', manifest, re.IGNORECASE)
+    if match and isinstance(group := match.group(1), str):
+        return group
+
+    raise ValueError
diff --git a/po/POTFILES.in b/po/POTFILES.in
index b88289a..8f4600d 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -1,6 +1,7 @@
 cartridges/application.py
 cartridges/games.py
-cartridges/sources.py
+cartridges/sources/__init__.py
+cartridges/sources/steam.py
 cartridges/ui/cover.blp
 cartridges/ui/cover.py
 cartridges/ui/game-details.blp