diff --git a/config/config.default.php b/config/config.default.php
index c1b322511..bb19ddf86 100644
--- a/config/config.default.php
+++ b/config/config.default.php
@@ -1,42 +1,87 @@
 <?php
 /**
- * Default configuration for Xhgui
+ * Default configuration for XHGui.
+ *
+ * To change these, create a called `config.php` file in the same directory,
+ * and return an array from there with your overriding settings.
  */
+
 return array(
-    'debug' => false,
-    'mode' => 'development',
-
-    // Can be either mongodb or file.
-    /* 
-    'save.handler' => 'file',
-    'save.handler.filename' => dirname(__DIR__) . '/cache/' . 'xhgui.data.' . microtime(true) . '_' . substr(md5($url), 0, 6),
-    */
+    // Which backend to use for Xhgui_Saver.
+    // Must be one of 'mongodb', or 'file'.
+    //
+    // Example (save to a temporary file):
+    //
+    //     'save.handler' => 'file',
+    //     # Beware of file locking. You can adujst this file path
+    //     # to reduce locking problems (eg uniqid, time ...)
+    //     'save.handler.filename' => __DIR__.'/../data/xhgui_'.date('Ymd').'.dat',
+    //
     'save.handler' => 'mongodb',
 
-    // Needed for file save handler. Beware of file locking. You can adujst this file path 
-    // to reduce locking problems (eg uniqid, time ...)
-    //'save.handler.filename' => __DIR__.'/../data/xhgui_'.date('Ymd').'.dat',
+    // Database options for MongoDB.
+    //
+    // - db.host: Connection string in the form `mongodb://[ip or host]:[port]`.
+    //
+    // - db.db: The database name.
+    //
+    // - db.options: Additional options for the MongoClient contructor,
+    //               for example 'username', 'password', or 'replicaSet'.
+    //               See <https://secure.php.net/mongoclient_construct#options>.
+    //
     'db.host' => 'mongodb://127.0.0.1:27017',
     'db.db' => 'xhprof',
-
-    // Allows you to pass additional options like replicaSet to MongoClient.
-    // 'username', 'password' and 'db' (where the user is added)
     'db.options' => array(),
-    'templates.path' => dirname(__DIR__) . '/src/templates',
-    'date.format' => 'M jS H:i:s',
-    'detail.count' => 6,
-    'page.limit' => 25,
 
-    // Profile 1 in 100 requests.
-    // You can return true to profile every request.
+    // Whether to instrument a user request.
+    //
+    // NOTE: Only applies to using the external/header.php include.
+    //
+    // Must be a function that returns a boolean,
+    // or any non-function value to disable the profiler.
+    //
+    // Default: Profile 1 in 100 requests.
+    //
+    // Example (profile all requests):
+    //
+    //     'profiler.enabled' => function() {
+    //         return true;
+    //     },
+    //
     'profiler.enable' => function() {
         return rand(1, 100) === 42;
     },
 
-    'profiler.simple_url' => function($url) {
-        return preg_replace('/\=\d+/', '', $url);
-    },
+    // Transformation for the "simple" variant of the URL.
+    // This is stored as `meta.simple_url` and used for
+    // aggregate data.
+    //
+    // NOTE: Only applies to using the external/header.php include.
+    //
+    // Must be a function that returns a string, or any
+    // non-callable value for the default behaviour.
+    //
+    // Default: Remove numeric values after `=`. For example,
+    // it turns "/foo?page=2" into "/foo?page".
+    'profiler.simple_url' => null,
 
+    // Additional options to be passed to the `_enable()` function
+    // of the profiler extension (xhprof, tideways, etc.).
+    //
+    // NOTE: Only applies to using the external/header.php include.
     'profiler.options' => array(),
 
+    // Date format used when browsing XHGui pages.
+    //
+    // Must be a format supported by the PHP date() function.
+    // See <https://secure.php.net/date>.
+    'date.format' => 'M jS H:i:s',
+
+    // The number of items to show in "Top lists" with functions
+    // using the most time or memory resources, on XHGui Run pages.
+    'detail.count' => 6,
+
+    // The number of items to show per page, on XHGui list pages.
+    'page.limit' => 25,
+
 );