Clarify == case

drafts/macaroons_caveats.rst

@@ -17,9 +17,9 @@ And these are joined by single space characters.
 
 Specified caveats:
 
-+-------------+--------------------------------------------------+--------------------------------------------------------------------------------------------+
++-------------+--------------------------------------------------+------------------------------------------------------------------------------------------------+
 | Caveat name | Description                                      | Legal Values                                                                                   |
-+-------------+--------------------------------------------------+--------------------------------------------------------------------------------------------+
++-------------+--------------------------------------------------+------------------------------------------------------------------------------------------------+
 | gen         | Generation of the macaroon caveat spec.          | 1                                                                                              |
 | user_id     | ID of the user for which this macaroon is valid. | Pure equality check. Operator must be =.                                                       |
 | type        | The purpose of this macaroon.                    | access - used to authorize any action except token refresh                                     |
@@ -27,4 +27,6 @@ Specified caveats:
 | time        | Time before/after which this macaroon is valid.  | A POSIX timestamp in milliseconds (in UTC).                                                    |
 |                                                                  Operator < means the macaroon is valid before the timestamp, as interpreted by the server.     |
 |                                                                  Operator > means the macaroon is valid after the timestamp, as interpreted by the server.      |
-+-------------+--------------------------------------------------+--------------------------------------------------------------------------------------------+
+|                                                                  Operator == means the macaroon is valid at exactly the timestamp, as interpreted by the server.|
+|                                                                  Note that exact equality of time is largely meaningless.                                       |
++-------------+--------------------------------------------------+------------------------------------------------------------------------------------------------+