mapCustomInstallPaths example

        $availableVars = $this->inflectPackageVars(compact('name', 'vendor', 'type'));

        $extra = $package->getExtra();
        if (!empty($extra['installer-name'])) {
            $availableVars['name'] = $extra['installer-name'];
        }

        $extra = $this->composer->getPackage()->getExtra();
        if (!empty($extra['installer-paths'])) {
            $customPath = $this->mapCustomInstallPaths($extra['installer-paths'], $prettyName, $type, $vendor);
            if ($customPath !== false) {
                return $this->templatePath($customPath, $availableVars);
            }
        }

        $packageType = substr($type, strlen($frameworkType) + 1);
        $locations = $this->getLocations($frameworkType);
        if (!isset($locations[$packageType])) {
            throw new \InvalidArgumentException(sprintf('Package type "%s" is not supported', $type));
        }