diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/resource/AppCacheManifestTransformer.java b/spring-webflux/src/main/java/org/springframework/web/reactive/resource/AppCacheManifestTransformer.java
index f77eed5346b..99c130389db 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/resource/AppCacheManifestTransformer.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/resource/AppCacheManifestTransformer.java
@@ -65,7 +65,9 @@ import org.springframework.web.server.ServerWebExchange;
  * @author Brian Clozel
  * @since 5.0
  * @see <a href="https://html.spec.whatwg.org/multipage/browsers.html#offline">HTML5 offline applications spec</a>
+ * @deprecated as of 5.3 since browser support is going away, scheduled for removal in 6.0.
  */
+@Deprecated
 public class AppCacheManifestTransformer extends ResourceTransformerSupport {
 
 	private static final String MANIFEST_HEADER = "CACHE MANIFEST";
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/AppCacheManifestTransformer.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/AppCacheManifestTransformer.java
index eb3253e1328..8d80ed678a2 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/AppCacheManifestTransformer.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/AppCacheManifestTransformer.java
@@ -62,7 +62,9 @@ import org.springframework.util.StringUtils;
  * @author Brian Clozel
  * @since 4.1
  * @see <a href="https://html.spec.whatwg.org/multipage/browsers.html#offline">HTML5 offline applications spec</a>
+ * @deprecated as of 5.3 since browser support is going away, scheduled for removal in 6.0.
  */
+@Deprecated
 public class AppCacheManifestTransformer extends ResourceTransformerSupport {
 
 	private static final String MANIFEST_HEADER = "CACHE MANIFEST";