use url as entry label if title is not defined.

lib/src/internal/extension_utils.dart

@@ -34,6 +34,17 @@ extension ObjectExt<T> on T {
   R let<R>(R Function(T that) op) => op(this);
 }
 
+extension StringExt on String {
+  String takeUnlessBlank() => nullIfBlank();
+
+  String nullIfBlank() {
+    if (this == null || isEmpty) {
+      return null;
+    }
+    return this;
+  }
+}
+
 extension IterableExt<T> on Iterable<T> {
   T get singleOrNull => singleWhere((element) => true, orElse: () => null);
 }

lib/src/kdbx_entry.dart

@@ -325,7 +325,8 @@ class KdbxEntry extends KdbxObject {
   }
 
   String get label =>
-      _plainValue(KdbxKeyCommon.TITLE) ?? _plainValue(KdbxKeyCommon.URL);
+      _plainValue(KdbxKeyCommon.TITLE)?.takeUnlessBlank() ??
+      _plainValue(KdbxKeyCommon.URL)?.takeUnlessBlank();
 
   set label(String label) => setString(KdbxKeyCommon.TITLE, PlainValue(label));