diff --git a/libdiscover/Category/Category.h b/libdiscover/Category/Category.h
--- a/libdiscover/Category/Category.h
+++ b/libdiscover/Category/Category.h
@@ -68,6 +68,12 @@
 
     static void sortCategories(QVector<Category*>& cats);
     static void addSubcategory(QVector<Category*>& cats, Category* cat);
+    /**
+     * Add a subcategory to this category. This function should only
+     * be used during the initialisation stage, before adding the local
+     * root category to the global root category model.
+     */
+    void addSubcategory(Category* cat);
     void parseData(const QString& path, const QDomNode& data);
     bool blacklistPlugins(const QSet<QString>& pluginName);
     bool isAddons() const { return m_isAddons; }
diff --git a/libdiscover/Category/Category.cpp b/libdiscover/Category/Category.cpp
--- a/libdiscover/Category/Category.cpp
+++ b/libdiscover/Category/Category.cpp
@@ -222,6 +222,19 @@
     Q_ASSERT(isSorted(list));
 }
 
+void Category::addSubcategory(Category* cat)
+{
+    int i = 0;
+    for(Category* subCat : m_subCategories) {
+        if(!categoryLessThan(subCat, cat)) {
+            break;
+        }
+        ++i;
+    }
+    m_subCategories.insert(i, cat);
+    Q_ASSERT(isSorted(m_subCategories));
+}
+
 bool Category::blacklistPluginsInVector(const QSet<QString>& pluginNames, QVector<Category *>& subCategories)
 {
     bool ret = false;
diff --git a/libdiscover/backends/KNSBackend/KNSBackend.cpp b/libdiscover/backends/KNSBackend/KNSBackend.cpp
--- a/libdiscover/backends/KNSBackend/KNSBackend.cpp
+++ b/libdiscover/backends/KNSBackend/KNSBackend.cpp
@@ -143,6 +143,17 @@
             categories << new Category(cat, {}, { {CategoryFilter, cat } }, backendName, {}, {}, true);
     }
 
+    QVector<Category*> topCategories{categories};
+    for (const auto &cat: categories) {
+        const QString catName = cat->name().append(QLatin1Char('/'));
+        for (const auto& potentialSubCat: categories) {
+            if(potentialSubCat->name().startsWith(catName)) {
+                cat->addSubcategory(potentialSubCat);
+                topCategories.removeOne(potentialSubCat);
+            }
+        }
+    }
+
     m_engine = new KNSCore::Engine(this);
     connect(m_engine, &KNSCore::Engine::signalErrorCode, this, &KNSBackend::signalErrorCode);
     connect(m_engine, &KNSCore::Engine::signalEntriesLoaded, this, &KNSBackend::receivedEntries, Qt::QueuedConnection);