Flarum\Extension\ExtensionManager::enable PHP Method

    public function enable($name)
    {
        if (!$this->isEnabled($name)) {
            $extension = $this->getExtension($name);
            $enabled = $this->getEnabled();
            $enabled[] = $name;
            $this->migrate($extension);
            $this->publishAssets($extension);
            $this->setEnabled($enabled);
            $extension->setEnabled(true);
            $this->dispatcher->fire(new ExtensionWasEnabled($extension));
        }
    }

 /**
  * {@inheritdoc}
  */
 public function handle(ServerRequestInterface $request)
 {
     $this->assertAdminAndSudo($request);
     $enabled = array_get($request->getParsedBody(), 'enabled');
     $name = array_get($request->getQueryParams(), 'name');
     if ($enabled === true) {
         $this->extensions->enable($name);
     } elseif ($enabled === false) {
         $this->extensions->disable($name);
     }
 }