system/Router/RouteCollection.php
public function environment(string $env, \Closure $callback): RouteCollectionInterface
	{
		if (ENVIRONMENT === $env)
		{
			$callback($this);
		}

		return $this;
	}
public function environment(string $env, \Closure $callback): RouteCollectionInterface
	{
		if (ENVIRONMENT === $env)
		{
			$callback($this);
		}

		return $this;
	}
Limits the routes to a specified ENVIRONMENT or they won't run.

@param string   $env
@param \Closure $callback

@return RouteCollectionInterface