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+# Expires attribute in `Set-Cookie` headers
+
+The `Expires` attribute in a `Set-Cookie` header defines when the cookie should expire.
+
+It must follow the **RFC 6265** date format:
+
+⚠️ **Notes:**
+- The date must use the `GMT` timezone.
+- Invalid formats or missing timezone cause browsers to ignore the cookie.
+- When using `Max-Age`, `Expires` may be omitted.