diff --git a/qa/system-indices/src/javaRestTest/java/org/elasticsearch/system/indices/NetNewSystemIndicesIT.java b/qa/system-indices/src/javaRestTest/java/org/elasticsearch/system/indices/NetNewSystemIndicesIT.java
index f345b79a377e7..efa815756b582 100644
--- a/qa/system-indices/src/javaRestTest/java/org/elasticsearch/system/indices/NetNewSystemIndicesIT.java
+++ b/qa/system-indices/src/javaRestTest/java/org/elasticsearch/system/indices/NetNewSystemIndicesIT.java
@@ -10,7 +10,6 @@
 package org.elasticsearch.system.indices;
 
 import org.apache.http.util.EntityUtils;
-import org.elasticsearch.Version;
 import org.elasticsearch.client.Request;
 import org.elasticsearch.client.Response;
 import org.elasticsearch.client.ResponseException;
@@ -36,7 +35,7 @@ protected Settings restClientSettings() {
     public void testCreatingSystemIndex() throws Exception {
         ResponseException e = expectThrows(
             ResponseException.class,
-            () -> client().performRequest(new Request("PUT", "/.net-new-system-index-" + Version.CURRENT.major))
+            () -> client().performRequest(new Request("PUT", "/.net-new-system-index-primary"))
         );
         assertThat(EntityUtils.toString(e.getResponse().getEntity()), containsString("system"));
 
@@ -48,7 +47,7 @@ public void testIndexDoc() throws Exception {
         String id = randomAlphaOfLength(4);
 
         ResponseException e = expectThrows(ResponseException.class, () -> {
-            Request request = new Request("PUT", "/.net-new-system-index-" + Version.CURRENT.major + "/_doc" + id);
+            Request request = new Request("PUT", "/.net-new-system-index-primary/_doc" + id);
             request.setJsonEntity("{}");
             client().performRequest(request);
         });
@@ -91,7 +90,7 @@ public void testSearch() throws Exception {
         assertThat(EntityUtils.toString(searchResponse.getEntity()), not(containsString(".net-new")));
 
         // direct index search
-        Request directRequest = new Request("GET", "/.net-new-system-index-" + Version.CURRENT.major + "/_search");
+        Request directRequest = new Request("GET", "/.net-new-system-index-primary/_search");
         directRequest.setJsonEntity("{ \"query\": { \"match_all\": {} } }");
         directRequest.addParameter("size", "10000");
         ResponseException e = expectThrows(ResponseException.class, () -> client().performRequest(directRequest));
diff --git a/qa/system-indices/src/main/java/org/elasticsearch/system/indices/SystemIndicesQA.java b/qa/system-indices/src/main/java/org/elasticsearch/system/indices/SystemIndicesQA.java
index d4b242e613c95..e6325d8bad6f6 100644
--- a/qa/system-indices/src/main/java/org/elasticsearch/system/indices/SystemIndicesQA.java
+++ b/qa/system-indices/src/main/java/org/elasticsearch/system/indices/SystemIndicesQA.java
@@ -9,7 +9,6 @@
 
 package org.elasticsearch.system.indices;
 
-import org.elasticsearch.Version;
 import org.elasticsearch.action.admin.indices.create.CreateIndexRequest;
 import org.elasticsearch.action.index.IndexRequest;
 import org.elasticsearch.client.internal.node.NodeClient;
@@ -76,7 +75,7 @@ public Collection<SystemIndexDescriptor> getSystemIndexDescriptors(Settings sett
                 )
                 .setOrigin(TASKS_ORIGIN)
                 .setVersionMetaKey("version")
-                .setPrimaryIndex(".net-new-system-index-" + Version.CURRENT.major)
+                .setPrimaryIndex(".net-new-system-index-primary")
                 .build(),
             SystemIndexDescriptor.builder()
                 .setIndexPattern(INTERNAL_UNMANAGED_INDEX_NAME)
@@ -99,7 +98,7 @@ public Collection<SystemIndexDescriptor> getSystemIndexDescriptors(Settings sett
                 )
                 .setOrigin(TASKS_ORIGIN)
                 .setVersionMetaKey("version")
-                .setPrimaryIndex(".internal-managed-index-" + Version.CURRENT.major)
+                .setPrimaryIndex(".internal-managed-index-primary")
                 .setAliasName(".internal-managed-alias")
                 .build()
         );
@@ -110,7 +109,6 @@ private static XContentBuilder mappings() {
             return jsonBuilder().startObject()
                 .startObject(SINGLE_MAPPING_NAME)
                 .startObject("_meta")
-                .field("version", Version.CURRENT)
                 .field(SystemIndexDescriptor.VERSION_META_KEY, 1)
                 .endObject()
                 .field("dynamic", "strict")
@@ -155,7 +153,7 @@ public List<Route> routes() {
         protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
             return channel -> client.admin()
                 .indices()
-                .create(new CreateIndexRequest(".net-new-system-index-" + Version.CURRENT.major), new RestToXContentListener<>(channel));
+                .create(new CreateIndexRequest(".net-new-system-index-primary"), new RestToXContentListener<>(channel));
         }
 
         @Override
@@ -177,7 +175,7 @@ public List<Route> routes() {
 
         @Override
         protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
-            IndexRequest indexRequest = new IndexRequest(".net-new-system-index-" + Version.CURRENT.major);
+            IndexRequest indexRequest = new IndexRequest(".net-new-system-index-primary");
             indexRequest.source(request.requiredContent(), request.getXContentType());
             indexRequest.id(request.param("id"));
             indexRequest.setRefreshPolicy(request.param("refresh"));
diff --git a/server/src/main/java/org/elasticsearch/common/logging/HeaderWarning.java b/server/src/main/java/org/elasticsearch/common/logging/HeaderWarning.java
index 20ed4611106ac..090f126fcaa9c 100644
--- a/server/src/main/java/org/elasticsearch/common/logging/HeaderWarning.java
+++ b/server/src/main/java/org/elasticsearch/common/logging/HeaderWarning.java
@@ -117,8 +117,9 @@ static Pattern getPatternWithoutSemanticVersion() {
      * three-digit number with various standard warn codes specified. The warn code 299 is apt for our purposes as it represents a
      * miscellaneous persistent warning (can be presented to a human, or logged, and must not be removed by a cache). The warn-agent is an
      * arbitrary token; here we use the Elasticsearch version and build hash, if the version is semantic, or just the hash, if it is not
-     * semantic (e.g. in serverless). The warn text must be quoted. The warn-date is an optional quoted field that can be in a variety of
-     * specified date formats; here we use RFC 1123 format.
+     * semantic (e.g. overridden with an arbitrary string by a org.elasticsearch.internal.BuildExtension implementation).
+     * The warn text must be quoted. The warn-date is an optional quoted field that can be in a variety of specified date formats; here we
+     * use RFC 1123 format.
      */
     private static final String WARNING_PREFIX = buildWarningPrefix();
 
@@ -205,6 +206,7 @@ public static void removeThreadContext(ThreadContext threadContext) {
      * {@code 299 Elasticsearch-6.0.0 "warning value"}, the return value of this method would be {@code warning value}.
      *
      * @param s the value of a warning header formatted according to RFC 7234.
+     * @param stripXContentPosition whether to remove XContent location information or not
      * @return the extracted warning value
      */
     public static String extractWarningValueFromWarningHeader(final String s, boolean stripXContentPosition) {