public function getUploader( int $audience = self::FOR_PUBLIC, Authority $performer = null ): ?UserIdentity {
        $this->load();
        if ( $audience === self::FOR_PUBLIC && $this->isDeleted( File::DELETED_USER ) ) {
            return null;
        } elseif ( $audience === self::FOR_THIS_USER && !$this->userCan( File::DELETED_USER, $performer ) ) {