what are Properties injection?

what are Properties injection? ,look code

/** @var \Phalcon\Mvc\Model\Query\BuilderInterface $itemBuilder */
    $itemBuilder = $this
        ->modelsManager
        ->createBuilder()
        ->from(['p' => 'Phosphorum\Models\Posts'])
        ->orderBy('p.sticked DESC, p.created_at DESC');

and

/**
 * Class PostsVotes
 *
 * @property \Phosphorum\Models\Posts post
 * @property \Phosphorum\Models\Users user
 *
 * @package Phosphorum\Models
 */

I didn't find relevant documents

This is not an injection. This is just for autocomplete in phpstorm for example. If you will access property post from object of PostVotes it will autocomplete that this is \Phosphorum\Models\Posts class, without it it wouldn't be recognized what is it.