Setting up debug mode on Drupal 8

  1. First copy sites/example.settings.local.php to default/settings.local.php
  2. Now uncomment the following lines in default/settings.php
    # if (file_exists(__DIR__ . '/settings.local.php')) {
    #   include __DIR__ . '/settings.local.php';
    # }
  3. Now debugging is set. You also can use the following command
    drupal routing:debug <route name>
    This command will give the user information regarding a specific route


  4.  Further also  use the devel module 
    • First install using drush en devel
    • enable the webprofiler module as well
    • Got to webprofiler config page, and check the following check boxes Events, Routing and Services
    • Now at the bottom of every page you gete the profiler bar which gives you lots of information
      • web profiler