src/includes/classes/Core/Utils/Url.php
public function normalizeAmps(string $qs_url_uri): string
    {
        if (!$qs_url_uri) {
            return $qs_url_uri; // Possible `0`.
        }
        if (($regex_amps = &$this->cacheKey(__FUNCTION__.'_regex_amps')) === null) {
            $regex_amps = implode('|', array_keys($this::HTML_AMPERSAND_ENTITIES));
        }
        return preg_replace('/(?:'.$regex_amps.')/uS', '&', $qs_url_uri);
    }
public function normalizeAmps(string $qs_url_uri): string
    {
        if (!$qs_url_uri) {
            return $qs_url_uri; // Possible `0`.
        }
        if (($regex_amps = &$this->cacheKey(__FUNCTION__.'_regex_amps')) === null) {
            $regex_amps = implode('|', array_keys($this::HTML_AMPERSAND_ENTITIES));
        }
        return preg_replace('/(?:'.$regex_amps.')/uS', '&', $qs_url_uri);
    }
Normalize ampersands.

@since 150424 Initial release.

@param string $qs_url_uri A query string (w/ or w/o a leading `?`), a URL, or URI.

@return string The `$qs_url_uri` w/ normalized ampersands.