diff --git a/gradle/changelog/contentTypeResolverExtension.yaml b/gradle/changelog/contentTypeResolverExtension.yaml
new file mode 100644
index 0000000000..2e2dbec4ee
--- /dev/null
+++ b/gradle/changelog/contentTypeResolverExtension.yaml
@@ -0,0 +1,2 @@
+- type: added
+  description: Add api to overwrite content type resolver ([#2051](https://github.com/scm-manager/scm-manager/pull/2051))
diff --git a/scm-core/src/main/java/sonia/scm/io/ContentTypeResolverExtension.java b/scm-core/src/main/java/sonia/scm/io/ContentTypeResolverExtension.java
new file mode 100644
index 0000000000..0562951315
--- /dev/null
+++ b/scm-core/src/main/java/sonia/scm/io/ContentTypeResolverExtension.java
@@ -0,0 +1,41 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.io;
+
+import sonia.scm.plugin.ExtensionPoint;
+
+import java.util.Optional;
+
+/**
+ * ContentTypeResolverExtension extends the default {@link ContentTypeResolver} with custom resolve actions.
+ * This can be used by plugins which want to change the content type of specific file extensions.
+ *
+ * @since 2.36.0
+ */
+@ExtensionPoint
+public interface ContentTypeResolverExtension {
+
+  Optional<String> resolve(String path, byte[] contentPrefix);
+}
diff --git a/scm-ui/ui-webapp/src/repos/sources/containers/SourcesView.tsx b/scm-ui/ui-webapp/src/repos/sources/containers/SourcesView.tsx
index cecde05b68..bd9e103da0 100644
--- a/scm-ui/ui-webapp/src/repos/sources/containers/SourcesView.tsx
+++ b/scm-ui/ui-webapp/src/repos/sources/containers/SourcesView.tsx
@@ -81,7 +81,7 @@ const SourcesView: FC<Props> = ({ file, repository, revision }) => {
           file,
           contentType,
           revision,
-          basePath
+          basePath,
         }}
       >
         <DownloadViewer repository={repository} file={file} />
diff --git a/scm-webapp/src/main/java/sonia/scm/io/DefaultContentTypeResolver.java b/scm-webapp/src/main/java/sonia/scm/io/DefaultContentTypeResolver.java
index 033232c3b7..c7831f8087 100644
--- a/scm-webapp/src/main/java/sonia/scm/io/DefaultContentTypeResolver.java
+++ b/scm-webapp/src/main/java/sonia/scm/io/DefaultContentTypeResolver.java
@@ -24,15 +24,20 @@
 
 package sonia.scm.io;
 
+import com.cloudogu.spotter.ContentType;
 import com.cloudogu.spotter.ContentTypeDetector;
 import com.cloudogu.spotter.Language;
 
+import javax.inject.Inject;
 import java.util.Collections;
 import java.util.Map;
 import java.util.Optional;
+import java.util.Set;
 
 public final class DefaultContentTypeResolver implements ContentTypeResolver {
 
+  private final Set<ContentTypeResolverExtension> resolverExtensions;
+
   private static final Language[] BOOST = new Language[]{
     // GCC Machine Description uses .md as extension, but markdown is much more likely
     Language.MARKDOWN,
@@ -52,14 +57,25 @@ public final class DefaultContentTypeResolver implements ContentTypeResolver {
     .boost(BOOST)
     .bestEffortMatch();
 
+  @Inject
+  public DefaultContentTypeResolver(Set<ContentTypeResolverExtension> resolverExtensions) {
+    this.resolverExtensions = resolverExtensions;
+  }
+
   @Override
   public DefaultContentType resolve(String path) {
-    return new DefaultContentType(PATH_BASED.detect(path));
+    Optional<String> extensionContentType = resolveContentTypeFromExtensions(path, new byte[]{});
+    return extensionContentType
+      .map(rawContentType -> new DefaultContentType(new ContentType(rawContentType)))
+      .orElseGet(() -> new DefaultContentType(PATH_BASED.detect(path)));
   }
 
   @Override
   public DefaultContentType resolve(String path, byte[] contentPrefix) {
-    return new DefaultContentType(PATH_AND_CONTENT_BASED.detect(path, contentPrefix));
+    Optional<String> extensionContentType = resolveContentTypeFromExtensions(path, contentPrefix);
+    return extensionContentType
+      .map(rawContentType -> new DefaultContentType(new ContentType(rawContentType)))
+      .orElseGet(() -> new DefaultContentType(PATH_AND_CONTENT_BASED.detect(path, contentPrefix)));
   }
 
   @Override
@@ -70,4 +86,12 @@ public final class DefaultContentTypeResolver implements ContentTypeResolver {
     }
     return Collections.emptyMap();
   }
+
+  private Optional<String> resolveContentTypeFromExtensions(String path, byte[] contentPrefix) {
+    return resolverExtensions.stream()
+      .map(r -> r.resolve(path, contentPrefix))
+      .filter(Optional::isPresent)
+      .map(Optional::get)
+      .findFirst();
+  }
 }
diff --git a/scm-webapp/src/test/java/sonia/scm/api/v2/resources/ContentResourceTest.java b/scm-webapp/src/test/java/sonia/scm/api/v2/resources/ContentResourceTest.java
index 0380027c12..1c56fdf8e8 100644
--- a/scm-webapp/src/test/java/sonia/scm/api/v2/resources/ContentResourceTest.java
+++ b/scm-webapp/src/test/java/sonia/scm/api/v2/resources/ContentResourceTest.java
@@ -46,6 +46,7 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.URL;
+import java.util.Collections;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
@@ -74,7 +75,7 @@ public class ContentResourceTest {
 
   @Before
   public void initService() throws Exception {
-    contentResource = new ContentResource(repositoryServiceFactory, new DefaultContentTypeResolver());
+    contentResource = new ContentResource(repositoryServiceFactory, new DefaultContentTypeResolver(Collections.emptySet()));
 
     NamespaceAndName existingNamespaceAndName = new NamespaceAndName(NAMESPACE, REPO_NAME);
     RepositoryService repositoryService = repositoryServiceFactory.create(existingNamespaceAndName);
diff --git a/scm-webapp/src/test/java/sonia/scm/api/v2/resources/DiffResultToDiffResultDtoMapperTest.java b/scm-webapp/src/test/java/sonia/scm/api/v2/resources/DiffResultToDiffResultDtoMapperTest.java
index 66ae5a9459..4098c01e2a 100644
--- a/scm-webapp/src/test/java/sonia/scm/api/v2/resources/DiffResultToDiffResultDtoMapperTest.java
+++ b/scm-webapp/src/test/java/sonia/scm/api/v2/resources/DiffResultToDiffResultDtoMapperTest.java
@@ -36,6 +36,7 @@ import sonia.scm.repository.api.DiffResult;
 import sonia.scm.repository.api.Hunk;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
 import java.util.OptionalInt;
@@ -53,7 +54,7 @@ class DiffResultToDiffResultDtoMapperTest {
   private static final Repository REPOSITORY = new Repository("1", "git", "space", "X");
 
   ResourceLinks resourceLinks = ResourceLinksMock.createMock(create("/scm/api/v2"));
-  DiffResultToDiffResultDtoMapper mapper = new DiffResultToDiffResultDtoMapper(resourceLinks, new DefaultContentTypeResolver());
+  DiffResultToDiffResultDtoMapper mapper = new DiffResultToDiffResultDtoMapper(resourceLinks, new DefaultContentTypeResolver(Collections.emptySet()));
 
   @Test
   void shouldMapDiffResult() {
diff --git a/scm-webapp/src/test/java/sonia/scm/io/DefaultContentTypeResolverTest.java b/scm-webapp/src/test/java/sonia/scm/io/DefaultContentTypeResolverTest.java
index 5ae03229a4..1060ffd764 100644
--- a/scm-webapp/src/test/java/sonia/scm/io/DefaultContentTypeResolverTest.java
+++ b/scm-webapp/src/test/java/sonia/scm/io/DefaultContentTypeResolverTest.java
@@ -24,19 +24,22 @@
 
 package sonia.scm.io;
 
+import com.google.common.collect.ImmutableSet;
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
 
 import java.nio.charset.StandardCharsets;
+import java.util.Collections;
 import java.util.Map;
+import java.util.Optional;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
 class DefaultContentTypeResolverTest {
 
-  private final DefaultContentTypeResolver contentTypeResolver = new DefaultContentTypeResolver();
+  private final DefaultContentTypeResolver contentTypeResolver = new DefaultContentTypeResolver(Collections.emptySet());
 
   @Test
   void shouldReturnPrimaryPart() {
@@ -56,6 +59,14 @@ class DefaultContentTypeResolverTest {
     assertThat(contentType.getRaw()).isEqualTo("application/pdf");
   }
 
+  @Test
+  void shouldReturnContentTypeFromExtension() {
+    DefaultContentTypeResolver contentTypeResolver = new DefaultContentTypeResolver(ImmutableSet.of((path, contentPrefix) -> Optional.of("scm/test")));
+
+    ContentType contentType = contentTypeResolver.resolve("hog.pdf");
+    assertThat(contentType.getRaw()).isEqualTo("scm/test");
+  }
+
   @Nested
   class IsTextTests {