src/Composer/Plugin.php
public function getExtra($name = null)
    {
        if ($name === null) {
            return $this->extra;
        }
        $arr = $this->extra;
        $bits = explode('.', $name);
        $last = array_pop($bits);
        foreach ($bits as $bit) {
            if (!isset($arr[$bit])) {
                $arr[$bit] = [];
            }
            $arr = &$arr[$bit];
        }
        if (isset($arr[$last])) {
            return $arr[$last];
        }
        return null;
    }
public function getExtra($name = null)
    {
        if ($name === null) {
            return $this->extra;
        }
        $arr = $this->extra;
        $bits = explode('.', $name);
        $last = array_pop($bits);
        foreach ($bits as $bit) {
            if (!isset($arr[$bit])) {
                $arr[$bit] = [];
            }
            $arr = &$arr[$bit];
        }
        if (isset($arr[$last])) {
            return $arr[$last];
        }
        return null;
    }
HELPER: