Flarum\Foundation\Application::publicPath PHP Method

    public function publicPath()
    {
        return $this->publicPath;
    }

 /**
  * {@inheritdoc}
  */
 public function data(ServerRequestInterface $request, Document $document)
 {
     $this->assertAdmin($request->getAttribute('actor'));
     $file = array_get($request->getUploadedFiles(), 'favicon');
     $tmpFile = tempnam($this->app->storagePath() . '/tmp', 'favicon');
     $file->moveTo($tmpFile);
     $extension = pathinfo($file->getClientFilename(), PATHINFO_EXTENSION);
     if ($extension !== 'ico') {
         $manager = new ImageManager();
         $encodedImage = $manager->make($tmpFile)->resize(64, 64, function ($constraint) {
             $constraint->aspectRatio();
             $constraint->upsize();
         })->encode('png');
         file_put_contents($tmpFile, $encodedImage);
         $extension = 'png';
     }
     $mount = new MountManager(['source' => new Filesystem(new Local(pathinfo($tmpFile, PATHINFO_DIRNAME))), 'target' => new Filesystem(new Local($this->app->publicPath() . '/assets'))]);
     if (($path = $this->settings->get('favicon_path')) && $mount->has($file = "target://{$path}")) {
         $mount->delete($file);
     }
     $uploadName = 'favicon-' . Str::lower(Str::quickRandom(8)) . '.' . $extension;
     $mount->move('source://' . pathinfo($tmpFile, PATHINFO_BASENAME), "target://{$uploadName}");
     $this->settings->set('favicon_path', $uploadName);
     return parent::data($request, $document);
 }