Legal
Cookies
There are two, both strictly necessary, and neither is set before you choose to sign in.
No banner, and why
This site sets no analytics, advertising or profiling cookies, so there is nothing to ask your consent for and no banner to dismiss. The two cookies below are needed for signing in to work at all, which is why they are exempt from consent.
sx_flow
Set the moment you press the Google button, deleted as soon as you come back. It carries a one-time value that lets the server check that the answer from Google belongs to the sign-in you started, and not to someone else's. It lasts ten minutes.
sx_session
Set once you have signed in, so the site knows you on the next page without sending you round Google again. It holds a random identifier and nothing about you. It lasts thirty days, and signing out deletes it immediately.
Refusing them
Blocking these cookies in your browser is entirely your right; signing in will simply not work, and the rest of the site is unaffected.