Only try to create embedded font collection for valid assets location

src/Avalonia.Base/Media/FontManager.cs

@@ -107,7 +107,7 @@ namespace Avalonia.Media
                     source = new Uri(key.BaseUri, source);
                 }
 
-                if (!_fontCollections.TryGetValue(source, out var fontCollection))
+                if (!_fontCollections.TryGetValue(source, out var fontCollection) && (source.IsAbsoluteResm() || source.IsAvares()))
                 {
                     var embeddedFonts = new EmbeddedFontCollection(source, source);
 

src/Avalonia.Themes.Simple/Accents/Base.xaml

@@ -76,7 +76,7 @@
       <SolidColorBrush x:Key="RefreshVisualizerBackground" Color="Transparent" />
     </ResourceDictionary>
   </ResourceDictionary.ThemeDictionaries>
-  <FontFamily x:Key="ContentControlThemeFontFamily">fonts://Inter#Inter, $Default</FontFamily>
+  <FontFamily x:Key="ContentControlThemeFontFamily">fonts:Inter#Inter, $Default</FontFamily>
   <Color x:Key="ThemeAccentColor">#CC119EDA</Color>
   <Color x:Key="ThemeAccentColor2">#99119EDA</Color>
   <Color x:Key="ThemeAccentColor3">#66119EDA</Color>

tests/Avalonia.Skia.UnitTests/Media/FontManagerImplTests.cs

@@ -76,5 +76,16 @@ namespace Avalonia.Skia.UnitTests.Media
                 Assert.Throws<InvalidOperationException>(() => new Typeface("resm:Avalonia.Skia.UnitTests.Assets?assembly=Avalonia.Skia.UnitTests#Unknown").GlyphTypeface);
             }
         }
+
+        [Fact]
+        public void Should_Return_False_For_Unregistered_FontCollection_Uri()
+        {
+            using (UnitTestApplication.Start(TestServices.MockPlatformRenderInterface.With(fontManagerImpl: new FontManagerImpl())))
+            {
+                var result = FontManager.Current.TryGetGlyphTypeface(new Typeface("fonts:invalid#Something"), out _);
+
+                Assert.False(result);
+            }
+        }
     }
 }