diff --git a/third_party/libuweave/src/macaroon_caveat_internal.h b/third_party/libuweave/src/macaroon_caveat_internal.h
index 46a72fb..d6e7b07 100644
--- a/third_party/libuweave/src/macaroon_caveat_internal.h
+++ b/third_party/libuweave/src/macaroon_caveat_internal.h
@@ -20,8 +20,7 @@
                               size_t mac_tag_size);
 
 typedef struct {
-  bool has_issued_time;
-  uint32_t issued_time;
+  uint32_t issued_time;  // 0 when invalid or not set.
 } UwMacaroonValidationState;
 
 bool uw_macaroon_caveat_init_validation_state_(