/**
 * Implements hook_plugin_filter_TYPE_alter().
 */
function {{ machine_name }}_plugin_filter_TYPE_alter(array &$definitions, array $extra, $consumer) {
  // Remove the "Help" block from the Block UI list.
  if ($consumer == 'block_ui') {
    unset($definitions['help_block']);
  }

  // If the theme is specified, remove the branding block from the Bartik theme.
  if (isset($extra['theme']) && $extra['theme'] === 'bartik') {
    unset($definitions['system_branding_block']);
  }

  // Remove the "Main page content" block from everywhere.
  unset($definitions['system_main_block']);
}