Kevin Reed (Springthrough) asked a question.
Does anyone know what conditions trigger this warning? What fields is is looking at? Can I turn this check off without turning off the other system status checks? I tried changing the min password length, but that didn't make it go away. This check doesn't seem to be mentioned in the documentation.

I finally had some time to dig into this today. This message is triggered by Telerik.Sitefinity.Authentication.AuthenticationSystemStatusRetriever.
The "Password requirements not configured" message appears when any open access membership provider has an empty password strength regex.
The parameters are a little confusing to me because we also have minRequiredNonalphanumericCharacters, minRequiredPasswordLength, newPasswordLength parameters, but those don't seem to affect this warning.
There is also an "Insecure Authentication Provider" message that is shown when any enabled OpenID Connect authentication provider has a nonce mode of Disabled or Remote Only.