I have a CSP REST web application where I'm using delegated authentication via basic authentication in the REST calls. When I do a call to the web app with correct user credentials, I get a CSPSESSIONID cookie back representing the CSP session, which has started for the user I'm logged in with.
And when I want to log out/end the CSP session with the "CacheLogout=end" query parameter, I get a 401 Unauthorized code back. But the csp session itself does get terminated, which means the logout call was successful.