Added an (experimental) Source override option for URLs that work with an existing Source but use a custom host (#271, #393) (#502)

lib/app_sources/fdroidrepo.dart

@@ -19,17 +19,6 @@ class FDroidRepo extends AppSource {
     ];
   }
 
-  @override
-  String standardizeURL(String url) {
-    RegExp standardUrlRegExp =
-        RegExp('^https?://.+/fdroid/([^/]+(/|\\?)|[^/]+\$)');
-    RegExpMatch? match = standardUrlRegExp.firstMatch(url.toLowerCase());
-    if (match == null) {
-      throw InvalidURLError(name);
-    }
-    return url.substring(0, match.end);
-  }
-
   @override
   Future<APKDetails> getLatestAPKDetails(
     String standardUrl,