--- a/mobile/android/base/java/org/mozilla/gecko/Experiments.java
+++ b/mobile/android/base/java/org/mozilla/gecko/Experiments.java
@@ -54,16 +54,19 @@ public class Experiments {
     public static final String URLBAR_SHOW_EV_CERT_OWNER = "urlbar-show-ev-cert-owner";
 
     // Play HLS videos in a VideoView (Bug 1313391)
     public static final String HLS_VIDEO_PLAYBACK = "hls-video-playback";
 
     // Make new activity stream panel available (to replace top sites) (Bug 1313316)
     public static final String ACTIVITY_STREAM = "activity-stream";
 
+    // Tabs tray: Arrange tabs in two columns in portrait mode
+    public static final String COMPACT_TABS = "compact-tabs";
+
     /**
      * Returns if a user is in certain local experiment.
      * @param experiment Name of experiment to look up
      * @return returns value for experiment or false if experiment does not exist.
      */
     public static boolean isInExperimentLocal(Context context, String experiment) {
         if (SwitchBoard.isInBucket(context, 0, 20)) {
             return Experiments.ONBOARDING3_A.equals(experiment);