diff --git a/src/widgets/previewjob.h b/src/widgets/previewjob.h
--- a/src/widgets/previewjob.h
+++ b/src/widgets/previewjob.h
@@ -189,10 +189,18 @@
      * Returns a list of all available preview plugins. The list
      * contains the basenames of the plugins' .desktop files (no path,
      * no .desktop).
-     * @return the list of plugins
+     * @return the list of all available plugins
      */
     static QStringList availablePlugins();
 
+    /**
+     * Returns a list of plugins that should be enabled by default, which is all plugins
+     * Minus the plugins specified in an internal blacklist
+     * @return the list of plugins that should be enabled by default
+     * @since 5.40
+     */
+    static QStringList defaultPlugins();
+
     /**
      * Returns a list of all supported MIME types. The list can
      * contain entries like text/ * (without the space).
diff --git a/src/widgets/previewjob.cpp b/src/widgets/previewjob.cpp
--- a/src/widgets/previewjob.cpp
+++ b/src/widgets/previewjob.cpp
@@ -735,6 +735,19 @@
     return result;
 }
 
+QStringList PreviewJob::defaultPlugins()
+{
+    QStringList blacklist = QStringList()
+                            << QStringLiteral("textthumbnail");
+
+    QStringList defaultPlugins = availablePlugins();
+    foreach (const QString plugin, blacklist) {
+        defaultPlugins.removeAll(plugin);
+    }
+
+    return defaultPlugins;
+}
+
 QStringList PreviewJob::supportedMimeTypes()
 {
     QStringList result;