code: public function onBootstrap()
      {
          if ($this->debug->parentInstance) {
              // only recored php/request info for root instance
              return;
          }
          $collectWas = $this->debug->setCfg('collect', true);
          $this->debug->groupSummary();
          $this->debug->group('environment', $this->debug->meta(array(
              'hideIfEmpty' => true,
              'level' => 'info',
          )));
          $this->logPhpInfo();
          $this->logServerVals();
          $this->logRequest();    // headers, cookies, post
          $this->debug->groupEnd();
          $this->debug->groupEnd();
          $this->debug->setCfg('collect', $collectWas);
      }
docs: debug.init subscriber
  
  @return void