diff --git a/core/api/current.txt b/core/api/current.txt
index d791d95..8c2ba08 100644
--- a/core/api/current.txt
+++ b/core/api/current.txt
@@ -668,6 +668,7 @@
     field public static final int debuggable = 16842767; // 0x101000f
     field public static final int defaultFocusHighlightEnabled = 16844130; // 0x1010562
     field public static final int defaultHeight = 16844021; // 0x10104f5
+    field @FlaggedApi("android.content.res.default_locale") public static final int defaultLocale;
     field public static final int defaultToDeviceProtectedStorage = 16844036; // 0x1010504
     field public static final int defaultValue = 16843245; // 0x10101ed
     field public static final int defaultWidth = 16844020; // 0x10104f4
@@ -6188,6 +6189,7 @@
     ctor public LocaleConfig(@NonNull android.os.LocaleList);
     method public int describeContents();
     method @NonNull public static android.app.LocaleConfig fromContextIgnoringOverride(@NonNull android.content.Context);
+    method @FlaggedApi("android.content.res.default_locale") @Nullable public java.util.Locale getDefaultLocale();
     method public int getStatus();
     method @Nullable public android.os.LocaleList getSupportedLocales();
     method public void writeToParcel(@NonNull android.os.Parcel, int);
diff --git a/core/java/android/app/ContextImpl.java b/core/java/android/app/ContextImpl.java
index a538247..08c18c8 100644
--- a/core/java/android/app/ContextImpl.java
+++ b/core/java/android/app/ContextImpl.java
@@ -3483,12 +3483,10 @@
 
         // only do this if the user already has more than one preferred locale
         if (r.getConfiguration().getLocales().size() > 1) {
-            LocaleConfig lc = LocaleConfig.fromContextIgnoringOverride(this);
-            mResourcesManager.setLocaleList(lc != null
-                    && lc.getSupportedLocales() != null
-                    && !lc.getSupportedLocales().isEmpty()
-                    ? lc.getSupportedLocales()
-                    : null);
+            LocaleConfig lc = getUserId() < 0
+                    ? LocaleConfig.fromContextIgnoringOverride(this)
+                    : new LocaleConfig(this);
+            mResourcesManager.setLocaleConfig(lc);
         }
     }
 
diff --git a/core/java/android/app/LocaleConfig.java b/core/java/android/app/LocaleConfig.java
index 1fdc516..369a781 100644
--- a/core/java/android/app/LocaleConfig.java
+++ b/core/java/android/app/LocaleConfig.java
@@ -16,9 +16,11 @@
 
 package android.app;
 
+import android.annotation.FlaggedApi;
 import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.annotation.SuppressLint;
 import android.content.Context;
 import android.content.res.Resources;
 import android.content.res.TypedArray;
@@ -30,6 +32,7 @@
 import android.util.Slog;
 import android.util.Xml;
 
+import com.android.internal.R;
 import com.android.internal.util.XmlUtils;
 
 import org.xmlpull.v1.XmlPullParserException;
@@ -39,7 +42,7 @@
 import java.lang.annotation.RetentionPolicy;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.LinkedHashSet;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
 import java.util.Set;
@@ -66,6 +69,8 @@
     public static final String TAG_LOCALE_CONFIG = "locale-config";
     public static final String TAG_LOCALE = "locale";
     private LocaleList mLocales;
+
+    private Locale mDefaultLocale;
     private int mStatus = STATUS_NOT_SPECIFIED;
 
     /**
@@ -193,8 +198,17 @@
         XmlUtils.beginDocument(parser, TAG_LOCALE_CONFIG);
         int outerDepth = parser.getDepth();
         AttributeSet attrs = Xml.asAttributeSet(parser);
-        // LinkedHashSet to preserve insertion order
-        Set<String> localeNames = new LinkedHashSet<>();
+
+        String defaultLocale = null;
+        if (android.content.res.Flags.defaultLocale()) {
+            TypedArray att = res.obtainAttributes(
+                    attrs, com.android.internal.R.styleable.LocaleConfig);
+            defaultLocale = att.getString(
+                    R.styleable.LocaleConfig_defaultLocale);
+            att.recycle();
+        }
+
+        Set<String> localeNames = new HashSet<>();
         while (XmlUtils.nextElementWithin(parser, outerDepth)) {
             if (TAG_LOCALE.equals(parser.getName())) {
                 final TypedArray attributes = res.obtainAttributes(
@@ -209,6 +223,15 @@
         }
         mStatus = STATUS_SUCCESS;
         mLocales = LocaleList.forLanguageTags(String.join(",", localeNames));
+        if (defaultLocale != null) {
+            if (localeNames.contains(defaultLocale)) {
+                mDefaultLocale = Locale.forLanguageTag(defaultLocale);
+            } else {
+                Slog.w(TAG, "Default locale specified that is not contained in the list: "
+                        + defaultLocale);
+                mStatus = STATUS_PARSING_FAILED;
+            }
+        }
     }
 
     /**
@@ -224,6 +247,17 @@
     }
 
     /**
+     * Returns the default locale if specified, otherwise null
+     *
+     * @return The default Locale or null
+     */
+    @SuppressLint("UseIcu")
+    @FlaggedApi(android.content.res.Flags.FLAG_DEFAULT_LOCALE)
+    public @Nullable Locale getDefaultLocale() {
+        return mDefaultLocale;
+    }
+
+    /**
      * Get the status of reading the resource file where the LocaleConfig was stored.
      *
      * <p>Distinguish "the application didn't provide the resource file" from "the application
diff --git a/core/java/android/app/ResourcesManager.java b/core/java/android/app/ResourcesManager.java
index 1ecb5d3..6009c29 100644
--- a/core/java/android/app/ResourcesManager.java
+++ b/core/java/android/app/ResourcesManager.java
@@ -120,9 +120,9 @@
     private final ReferenceQueue<Resources> mResourcesReferencesQueue = new ReferenceQueue<>();
 
     /**
-     * The list of locales the app declares it supports.
+     * The localeConfig of the app.
      */
-    private LocaleList mLocaleList = LocaleList.getEmptyLocaleList();
+    private LocaleConfig mLocaleConfig = new LocaleConfig(LocaleList.getEmptyLocaleList());
 
     private static class ApkKey {
         public final String path;
@@ -1612,18 +1612,19 @@
     }
 
     /**
-     * Returns the LocaleList current set
+     * Returns the LocaleConfig current set
      */
-    public LocaleList getLocaleList() {
-        return mLocaleList;
+    public LocaleConfig getLocaleConfig() {
+        return mLocaleConfig;
     }
 
     /**
-     * Sets the LocaleList of app's supported locales
+     * Sets the LocaleConfig of the app
      */
-    public void setLocaleList(LocaleList localeList) {
-        if ((localeList != null) && !localeList.isEmpty()) {
-            mLocaleList = localeList;
+    public void setLocaleConfig(LocaleConfig localeConfig) {
+        if ((localeConfig != null) && (localeConfig.getSupportedLocales() != null)
+                && !localeConfig.getSupportedLocales().isEmpty()) {
+            mLocaleConfig = localeConfig;
         }
     }
 
diff --git a/core/java/android/content/res/ResourcesImpl.java b/core/java/android/content/res/ResourcesImpl.java
index 5cc3b92..c7790bd 100644
--- a/core/java/android/content/res/ResourcesImpl.java
+++ b/core/java/android/content/res/ResourcesImpl.java
@@ -27,6 +27,8 @@
 import android.annotation.RawRes;
 import android.annotation.StyleRes;
 import android.annotation.StyleableRes;
+import android.app.LocaleConfig;
+import android.app.ResourcesManager;
 import android.compat.annotation.UnsupportedAppUsage;
 import android.content.pm.ActivityInfo;
 import android.content.pm.ActivityInfo.Config;
@@ -426,38 +428,59 @@
 
                 String[] selectedLocales = null;
                 String defaultLocale = null;
+                LocaleConfig lc = ResourcesManager.getInstance().getLocaleConfig();
                 if ((configChanges & ActivityInfo.CONFIG_LOCALE) != 0) {
                     if (locales.size() > 1) {
-                        String[] availableLocales;
-                        // The LocaleList has changed. We must query the AssetManager's
-                        // available Locales and figure out the best matching Locale in the new
-                        // LocaleList.
-                        availableLocales = mAssets.getNonSystemLocales();
-                        if (LocaleList.isPseudoLocalesOnly(availableLocales)) {
-                            // No app defined locales, so grab the system locales.
-                            availableLocales = mAssets.getLocales();
-                            if (LocaleList.isPseudoLocalesOnly(availableLocales)) {
-                                availableLocales = null;
+                        if (Flags.defaultLocale() && (lc.getDefaultLocale() != null)) {
+                            Locale[] intersection =
+                                    locales.getIntersection(lc.getSupportedLocales());
+                            mConfiguration.setLocales(new LocaleList(intersection));
+                            selectedLocales = new String[intersection.length];
+                            for (int i = 0; i < intersection.length; i++) {
+                                selectedLocales[i] =
+                                        adjustLanguageTag(intersection[i].toLanguageTag());
                             }
-                        }
+                            defaultLocale =
+                                    adjustLanguageTag(lc.getDefaultLocale().toLanguageTag());
+                        } else {
+                            String[] availableLocales;
+                            // The LocaleList has changed. We must query the AssetManager's
+                            // available Locales and figure out the best matching Locale in the new
+                            // LocaleList.
+                            availableLocales = mAssets.getNonSystemLocales();
+                            if (LocaleList.isPseudoLocalesOnly(availableLocales)) {
+                                // No app defined locales, so grab the system locales.
+                                availableLocales = mAssets.getLocales();
+                                if (LocaleList.isPseudoLocalesOnly(availableLocales)) {
+                                    availableLocales = null;
+                                }
+                            }
 
-                        if (availableLocales != null) {
-                            final Locale bestLocale = locales.getFirstMatchWithEnglishSupported(
-                                    availableLocales);
-                            if (bestLocale != null) {
-                                selectedLocales = new String[]{
-                                        adjustLanguageTag(bestLocale.toLanguageTag())};
-                                if (!bestLocale.equals(locales.get(0))) {
-                                    mConfiguration.setLocales(
-                                            new LocaleList(bestLocale, locales));
+                            if (availableLocales != null) {
+                                final Locale bestLocale = locales.getFirstMatchWithEnglishSupported(
+                                        availableLocales);
+                                if (bestLocale != null) {
+                                    selectedLocales = new String[]{
+                                            adjustLanguageTag(bestLocale.toLanguageTag())};
+                                    if (!bestLocale.equals(locales.get(0))) {
+                                        mConfiguration.setLocales(
+                                                new LocaleList(bestLocale, locales));
+                                    }
                                 }
                             }
                         }
                     }
                 }
                 if (selectedLocales == null) {
-                    selectedLocales = new String[]{
-                            adjustLanguageTag(locales.get(0).toLanguageTag())};
+                    if (Flags.defaultLocale() && (lc.getDefaultLocale() != null)) {
+                        selectedLocales = new String[locales.size()];
+                        for (int i = 0; i < locales.size(); i++) {
+                            selectedLocales[i] = adjustLanguageTag(locales.get(i).toLanguageTag());
+                        }
+                    } else {
+                        selectedLocales = new String[]{
+                                adjustLanguageTag(locales.get(0).toLanguageTag())};
+                    }
                 }
 
                 if (mConfiguration.densityDpi != Configuration.DENSITY_DPI_UNDEFINED) {
diff --git a/core/java/android/os/LocaleList.java b/core/java/android/os/LocaleList.java
index 82cdd28..d7e440b 100644
--- a/core/java/android/os/LocaleList.java
+++ b/core/java/android/os/LocaleList.java
@@ -153,21 +153,21 @@
 
     /**
      * Find the intersection between this LocaleList and another
-     * @return a String array of the Locales in both LocaleLists
+     * @return an array of the Locales in both LocaleLists
      * {@hide}
      */
     @NonNull
-    public String[] getIntersection(@NonNull LocaleList other) {
-        List<String> intersection = new ArrayList<>();
+    public Locale[] getIntersection(@NonNull LocaleList other) {
+        List<Locale> intersection = new ArrayList<>();
         for (Locale l1 : mList) {
             for (Locale l2 : other.mList) {
                 if (matchesLanguageAndScript(l2, l1)) {
-                    intersection.add(l1.toLanguageTag());
+                    intersection.add(l1);
                     break;
                 }
             }
         }
-        return intersection.toArray(new String[0]);
+        return intersection.toArray(new Locale[0]);
     }
 
     /**
diff --git a/core/res/res/values/attrs.xml b/core/res/res/values/attrs.xml
index 04fd70a..3496994 100644
--- a/core/res/res/values/attrs.xml
+++ b/core/res/res/values/attrs.xml
@@ -10090,6 +10090,15 @@
     <!-- Perceptual luminance of a color, in accessibility friendly color space. From 0 to 100. -->
     <attr name="lStar" format="float"/>
 
+    <!-- The attributes of the {@code <locale-config>} tag. -->
+    <!-- @FlaggedApi("android.content.res.default_locale") -->
+    <declare-styleable name="LocaleConfig">
+        <!-- The <a href="https://www.rfc-editor.org/rfc/bcp/bcp47.txt">IETF BCP47 language tag</a>
+       the strings in values/strings.xml (the default strings in the directory with no locale
+       qualifier) are in. -->
+        <attr name="defaultLocale" format="string"/>
+    </declare-styleable>
+
     <!-- The attributes of the {@code <locale>} tag within {@code <locale-config>}. -->
     <declare-styleable name="LocaleConfig_Locale">
         <!-- The <a href="https://www.rfc-editor.org/rfc/bcp/bcp47.txt">IETF BCP47 language tag</a>
diff --git a/core/res/res/values/public-staging.xml b/core/res/res/values/public-staging.xml
index adc7fe0..4cd4f63 100644
--- a/core/res/res/values/public-staging.xml
+++ b/core/res/res/values/public-staging.xml
@@ -110,6 +110,8 @@
   <eat-comment/>
 
   <staging-public-group type="attr" first-id="0x01bd0000">
+    <!-- @FlaggedApi("android.content.res.default_locale") -->
+    <public name="defaultLocale"/>
   </staging-public-group>
 
   <staging-public-group type="id" first-id="0x01bc0000">
diff --git a/core/tests/coretests/src/android/os/LocaleListTest.java b/core/tests/coretests/src/android/os/LocaleListTest.java
index 1f00a7a..88fc826 100644
--- a/core/tests/coretests/src/android/os/LocaleListTest.java
+++ b/core/tests/coretests/src/android/os/LocaleListTest.java
@@ -81,4 +81,49 @@
         // restore the original values
         LocaleList.setDefault(originalLocaleList, originalLocaleIndex);
     }
+
+    @SmallTest
+    public void testIntersection() {
+        LocaleList localesWithN = new LocaleList(
+                Locale.ENGLISH,
+                Locale.FRENCH,
+                Locale.GERMAN,
+                Locale.ITALIAN,
+                Locale.JAPANESE,
+                Locale.KOREAN,
+                Locale.CHINESE,
+                Locale.SIMPLIFIED_CHINESE,
+                Locale.TRADITIONAL_CHINESE,
+                Locale.FRANCE,
+                Locale.GERMANY,
+                Locale.JAPAN,
+                Locale.CANADA,
+                Locale.CANADA_FRENCH);
+        LocaleList localesWithE = new LocaleList(
+                Locale.ENGLISH,
+                Locale.FRENCH,
+                Locale.GERMAN,
+                Locale.JAPANESE,
+                Locale.KOREAN,
+                Locale.CHINESE,
+                Locale.SIMPLIFIED_CHINESE,
+                Locale.TRADITIONAL_CHINESE,
+                Locale.FRANCE,
+                Locale.GERMANY,
+                Locale.CANADA_FRENCH);
+        LocaleList localesWithNAndE = new LocaleList(
+                Locale.ENGLISH,
+                Locale.FRENCH,
+                Locale.GERMAN,
+                Locale.JAPANESE,
+                Locale.KOREAN,
+                Locale.CHINESE,
+                Locale.SIMPLIFIED_CHINESE,
+                Locale.TRADITIONAL_CHINESE,
+                Locale.FRANCE,
+                Locale.GERMANY,
+                Locale.CANADA_FRENCH);
+
+        assertEquals(localesWithNAndE, new LocaleList(localesWithE.getIntersection(localesWithN)));
+    }
 }
diff --git a/libs/androidfw/AssetManager2.cpp b/libs/androidfw/AssetManager2.cpp
index 7f22693..d056248 100644
--- a/libs/androidfw/AssetManager2.cpp
+++ b/libs/androidfw/AssetManager2.cpp
@@ -785,7 +785,7 @@
       has_locale = true;
     }
 
-    // if we don't have a result yet
+      // if we don't have a result yet
     if (!final_result ||
         // or this config is better before the locale than the existing result
         result->config.isBetterThanBeforeLocale(final_result->config, desired_config) ||
@@ -863,9 +863,12 @@
 
       // We can skip calling ResTable_config::match() if the caller does not care for the
       // configuration to match or if we're using the list of types that have already had their
-      // configuration matched.
+      // configuration matched. The exception to this is when the user has multiple locales set
+      // because the filtered list will then have values from multiple locales and we will need to
+      // call match() to make sure the current entry matches the config we are currently checking.
       const ResTable_config& this_config = type_entry->config;
-      if (!(use_filtered || ignore_configuration || this_config.match(desired_config))) {
+      if (!((use_filtered && (configurations_.size() == 1))
+          || ignore_configuration || this_config.match(desired_config))) {
         continue;
       }