diff --git a/core/java/android/content/res/AssetManager.java b/core/java/android/content/res/AssetManager.java
index e57882240e567..ecae52c3cd67a 100644
--- a/core/java/android/content/res/AssetManager.java
+++ b/core/java/android/content/res/AssetManager.java
@@ -666,6 +666,14 @@ public final class AssetManager implements AutoCloseable {
 
     /**
      * Get the locales that this asset manager contains data for.
+     *
+     * <p>On SDK 21 (Android 5.0: Lollipop) and above, Locale strings are valid
+     * <a href="https://tools.ietf.org/html/bcp47">BCP-47</a> language tags and can be
+     * parsed using {@link java.util.Locale#forLanguageTag(String)}.
+     *
+     * <p>On SDK 20 (Android 4.4W: Kitkat for watches) and below, locale strings
+     * are of the form {@code ll_CC} where {@code ll} is a two letter language code,
+     * and {@code CC} is a two letter country code.
      */
     public native final String[] getLocales();