FEATURE: on mobile display a rollup of unread and new on latest

app/assets/javascripts/discourse/models/nav_item.js

@@ -12,7 +12,13 @@ Discourse.NavItem = Discourse.Model.extend({
   displayName: function() {
     var categoryName = this.get('categoryName'),
         name = this.get('name'),
-        extra = { count: this.get('count') || 0 };
+        count = this.get('count') || 0;
+
+    if (name === 'latest' && !Discourse.Mobile.mobileView) {
+      count = 0;
+    }
+
+    var extra = { count: count };
 
     if (categoryName) {
       name = 'category';

app/assets/javascripts/discourse/models/topic-tracking-state.js.es6

@@ -266,6 +266,12 @@ const TopicTrackingState = Discourse.Model.extend({
   },
 
   lookupCount(name, category){
+
+    if (name === "latest") {
+      return this.lookupCount("new", category) +
+             this.lookupCount("unread", category);
+    }
+
     let categoryName = category ? Em.get(category, "name") : null;
     if(name === "new") {
       return this.countNew(categoryName);
@@ -278,6 +284,7 @@ const TopicTrackingState = Discourse.Model.extend({
       }
     }
   },
+
   loadStates(data) {
     // not exposed
     const states = this.states;

config/locales/client.en.yml

@@ -1567,7 +1567,10 @@ en:
       with_topics: "%{filter} topics"
       with_category: "%{filter} %{category} topics"
       latest:
-        title: "Latest"
+        title:
+          zero: "Latest"
+          one: "Latest (1)"
+          other: "Latest ({{count}})"
         help: "topics with recent posts"
       hot:
         title: "Hot"