Keep-alive enables HTTP clients that support the HTTP/1.1 protocol to keep the connection to the server opened and pipeline multiple requests over it. This can significantly improve the speed at which search results appear, as browsers do not need to re-negotiate a new session for every request.
This option was added in version 1.32.1028.0.
Although adding KeepAlive=Y may improve overall performance of the software, it is considered experimental.