List a newsletter's publishable keys

The read-only keys this newsletter's website page source may carry, live ones first and newest first. Needs settings: read.

No secret and no digest: a secret is shown once, by the call that minted it, and is never readable again. key_prefix is what you recognise a key by, and last_used_at is how you tell which key your deployed pages are actually calling before turning the other one off.

Revoked keys are hidden unless you ask for them. A key that was abused has to stay nameable, which is why revocation is a stamp rather than a deletion.