src/Helper/ViewCombinations.php
protected function calculateCacheKey()
    {
        $key = 'view_combination_' . strtolower(TL_MODE);

        // Authenticate the user - if this fails, we use an anonymous cache file.
        if ($this->authenticateUser()) {
            /** @noinspection PhpUndefinedFieldInspection */
            $key .= '_' . $this->getUser()->id;
        } else {
            $key .= '_anonymous';
        }

        return $key;
    }
protected function calculateCacheKey()
    {
        $key = 'view_combination_' . strtolower(TL_MODE);

        // Authenticate the user - if this fails, we use an anonymous cache file.
        if ($this->authenticateUser()) {
            /** @noinspection PhpUndefinedFieldInspection */
            $key .= '_' . $this->getUser()->id;
        } else {
            $key .= '_anonymous';
        }

        return $key;
    }
Try to load the combinations from cache.

@return string|null