android, where is the notification with tag: ranker_group fom

in android app when doing some log for active notifications when receiving fcm push notification,

          
StatusBarNotification[] activeNotifications = context.getSystemService(Context.NOTIFICATION_SERVICE).getActiveNotifications();
                       
for (int i=0; i<activeNotifications.length; i++) {
    StatusBarNotification activeNotification = activeNotifications[i];
    
    Log.w("+++", "+++ ["+i+"]: id: "+ activeNotification.getId() +
          ", tag:"+activeNotification.getTag());
}

after received a few fcm push notifications it starts to show someone with tag:ranker_group

+++ [0]: id: 73, tag:null
+++ [1]: id: 88, tag:null
+++ [2]: id: 52, tag:null
+++ [3]: id: 42, tag:null
+++ [4]: id: 2147483647, tag:ranker_group

what is this notification with tag:ranker_group and where it is from?

When there have been too many active notifications the newer arriving ones may not be shown on the system notification drawer. If in that case it would like to cancel some old notifications, can the notification with tag:ranker_group be cancelled? in this case:

NotificationManagerCompat.from(mAppContext).cancel(4);

or is there suggested way to cancel some old notifications?