Flarum\Extension\ExtensionServiceProvider::register PHP Method

    public function register()
    {
        $this->app->bind('flarum.extensions', 'Flarum\\Extension\\ExtensionManager');
        $bootstrappers = $this->app->make('flarum.extensions')->getEnabledBootstrappers();
        foreach ($bootstrappers as $file) {
            $bootstrapper = (require $file);
            $this->app->call($bootstrapper);
        }
    }