Remove the --experimental_includes_attribute_subpackage_traversal command line option.

RELNOTES[INC]: The --experimental_includes_attribute_subpackage_traversal command line option is not available anymore.

PiperOrigin-RevId: 568783488
Change-Id: I0b1624e2cee054e66101f2125d9657ec3d99678b
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCommon.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCommon.java
index f1961c7..ecb1d42 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCommon.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCommon.java
@@ -448,12 +448,7 @@
             .getExecPath(ruleContext.getConfiguration().isSiblingRepositoryLayout());
     result.add(rulePackage);
 
-    if (ruleContext
-            .getConfiguration()
-            .getOptions()
-            .get(CppOptions.class)
-            .experimentalIncludesAttributeSubpackageTraversal
-        && ruleContext.getRule().isAttributeValueExplicitlySpecified("includes")) {
+    if (ruleContext.getRule().isAttributeValueExplicitlySpecified("includes")) {
       PathFragment packageFragment =
           ruleContext
               .getLabel()
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java
index 55888c9..dd84ced8 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java
@@ -889,18 +889,6 @@
   public boolean disableExpandIfAllAvailableInFlagSet;
 
   @Option(
-      name = "experimental_includes_attribute_subpackage_traversal",
-      defaultValue = "true",
-      documentationCategory = OptionDocumentationCategory.UNDOCUMENTED,
-      effectTags = {OptionEffectTag.EXECUTION},
-      metadataTags = {OptionMetadataTag.EXPERIMENTAL},
-      help =
-          "If a cc target has loose headers checking, disabled layering check and an "
-              + "includes attribute set, it is allowed to include anything under its folder, even "
-              + "across subpackage boundaries.")
-  public boolean experimentalIncludesAttributeSubpackageTraversal;
-
-  @Option(
       name = "incompatible_disable_legacy_cc_provider",
       defaultValue = "true",
       documentationCategory = OptionDocumentationCategory.UNDOCUMENTED,