I've used \v support, or lack there of, to fingerprint web devices during security audits.

Whitespace is often defined as space, \t, \r, \n, and \v. However many specs, like HTTP, will sometimes exclude \v. Depending on the underline functions products use in their HTTP parsers, you can fingerprint servers, WAFs, proxies, load balancers, whatever when using \v to separate HTTP headers lines or name\value pairs