src/Leevel/Router/Router.php
protected function matchedPrefix(): ?string
    {
        $prefix = $this->matchedData[static::PREFIX];

        if (!$prefix || is_scalar($prefix)) {
            return $prefix;
        }

        $prefix = array_map(function ($item) {
            return $this->convertMatched(ucfirst($item));
        }, $prefix);

        return $this->matchedData[static::PREFIX] = implode('\\', $prefix);
    }
protected function matchedPrefix(): ?string
    {
        $prefix = $this->matchedData[static::PREFIX];

        if (!$prefix || is_scalar($prefix)) {
            return $prefix;
        }

        $prefix = array_map(function ($item) {
            return $this->convertMatched(ucfirst($item));
        }, $prefix);

        return $this->matchedData[static::PREFIX] = implode('\\', $prefix);
    }
取回控制器前缀

@return string