utils: Ignore non-Linux screenshots

Fixes #4105

backend/app/utils.py

@@ -114,6 +114,8 @@ def appstream2dict(appstream_url=None) -> dict[str, dict]:
             for i, screenshot in enumerate(screenshots):
                 attrs = {}
 
+                attrs["environment"] = screenshot.attrib.get("environment")
+
                 if component.attrib.get("type") == "desktop-application":
                     for caption in screenshot.findall("caption"):
                         if caption is not None:
@@ -178,6 +180,13 @@ def appstream2dict(appstream_url=None) -> dict[str, dict]:
                     app["screenshots"].append(attrs.copy())
             component.remove(screenshots)
 
+            if app["screenshots"] and not all(
+                sc["environment"] in ("windows", "macos") for sc in app["screenshots"]
+            ):
+                for sc in app["screenshots"][:]:
+                    if sc["environment"] in ("windows", "macos"):
+                        app["screenshots"].remove(sc)
+
         releases = component.find("releases")
         if releases is not None:
             app["releases"] = []