--- a/mobile/android/base/java/org/mozilla/gecko/mma/MmaDelegate.java
+++ b/mobile/android/base/java/org/mozilla/gecko/mma/MmaDelegate.java
@@ -135,17 +135,17 @@ public class MmaDelegate {
 
         // if selected tab is private, mma should be disabled.
         final boolean isInPrivateBrowsing = selectedTab != null && selectedTab.isPrivate();
         // only check Gecko Pref when Gecko is running
         return inExperiment && healthReport && !isInPrivateBrowsing;
     }
 
 
-    private static boolean isDefaultBrowser(Context context) {
+    public static boolean isDefaultBrowser(Context context) {
         final Intent viewIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.mozilla.org"));
         final ResolveInfo info = context.getPackageManager().resolveActivity(viewIntent, PackageManager.MATCH_DEFAULT_ONLY);
         if (info == null) {
             // No default is set
             return false;
         }
         final String packageName = info.activityInfo.packageName;
         return (TextUtils.equals(packageName, context.getPackageName()));

--- a/mobile/android/base/java/org/mozilla/gecko/telemetry/pingbuilders/TelemetryCorePingBuilder.java
+++ b/mobile/android/base/java/org/mozilla/gecko/telemetry/pingbuilders/TelemetryCorePingBuilder.java
@@ -15,16 +15,17 @@ import android.support.annotation.Worker
 import android.text.TextUtils;
 
 import android.util.Log;
 
 import org.mozilla.gecko.GeckoApp;
 import org.mozilla.gecko.GeckoProfile;
 import org.mozilla.gecko.GeckoSharedPrefs;
 import org.mozilla.gecko.Locales;
+import org.mozilla.gecko.mma.MmaDelegate;
 import org.mozilla.gecko.search.SearchEngine;
 import org.mozilla.gecko.sync.ExtendedJSONObject;
 import org.mozilla.gecko.telemetry.TelemetryOutgoingPing;
 import org.mozilla.gecko.util.DateUtil;
 import org.mozilla.gecko.Experiments;
 import org.mozilla.gecko.util.HardwareUtils;
 import org.mozilla.gecko.util.StringUtils;
 
@@ -45,16 +46,17 @@ public class TelemetryCorePingBuilder ex
 
     // For legacy reasons, this preference key is not namespaced with "core".
     private static final String PREF_SEQ_COUNT = "telemetry-seqCount";
 
     private static final String NAME = "core";
     private static final int VERSION_VALUE = 9; // For version history, see toolkit/components/telemetry/docs/core-ping.rst
     private static final String OS_VALUE = "Android";
 
+    private static final String DEFAULT_BROWSER = "defaultBrowser";
     private static final String ARCHITECTURE = "arch";
     private static final String CAMPAIGN_ID = "campaignId";
     private static final String CLIENT_ID = "clientId";
     private static final String DEFAULT_SEARCH_ENGINE = "defaultSearch";
     private static final String DEVICE = "device";
     private static final String DISTRIBUTION_ID = "distributionId";
     private static final String EXPERIMENTS = "experiments";
     private static final String LOCALE = "locale";
@@ -82,16 +84,17 @@ public class TelemetryCorePingBuilder ex
         // manufacturer because we're less likely to have manufacturers with similar names than we are for a
         // manufacturer to have two devices with the similar names (e.g. Galaxy S6 vs. Galaxy Note 6).
         final String deviceDescriptor =
                 StringUtils.safeSubstring(Build.MANUFACTURER, 0, 12) + '-' + StringUtils.safeSubstring(Build.MODEL, 0, 19);
 
         final Calendar nowCalendar = Calendar.getInstance();
         final DateFormat pingCreationDateFormat = new SimpleDateFormat("yyyy-MM-dd", Locale.US);
 
+        payload.put(DEFAULT_BROWSER, MmaDelegate.isDefaultBrowser(context));
         payload.put(ARCHITECTURE, HardwareUtils.getRealAbi());
         payload.put(DEVICE, deviceDescriptor);
         payload.put(LOCALE, Locales.getLanguageTag(Locale.getDefault()));
         payload.put(OS_VERSION, Integer.toString(Build.VERSION.SDK_INT)); // A String for cross-platform reasons.
         payload.put(PING_CREATION_DATE, pingCreationDateFormat.format(nowCalendar.getTime()));
         payload.put(TIMEZONE_OFFSET, DateUtil.getTimezoneOffsetInMinutesForGivenDate(nowCalendar));
         payload.putArray(EXPERIMENTS, Experiments.getActiveExperiments(context));
         synchronized (this) {