make/data/tzdata/leapseconds

*** 85,95 ****
  Leap    2008    Dec     31      23:59:60        +       S
  Leap    2012    Jun     30      23:59:60        +       S
  Leap    2015    Jun     30      23:59:60        +       S
  Leap    2016    Dec     31      23:59:60        +       S
  
  # POSIX timestamps for the data in this file:
  #updated 1467936000 (2016-07-08 00:00:00 UTC)
! #expires 1593302400 (2020-06-28 00:00:00 UTC)
  
! #       Updated through IERS Bulletin C58
! #       File expires on:  28 June 2020
--- 85,101 ----
  Leap    2008    Dec     31      23:59:60        +       S
  Leap    2012    Jun     30      23:59:60        +       S
  Leap    2015    Jun     30      23:59:60        +       S
  Leap    2016    Dec     31      23:59:60        +       S
  
+ # UTC timestamp when this leap second list expires.
+ # Any additional leap seconds will come after this.
+ # This Expires line is commented out for now,
+ # so that pre-2020a zic implementations do not reject this file.
+ #Expires 2020   Dec     28      00:00:00
+ 
  # POSIX timestamps for the data in this file:
  #updated 1467936000 (2016-07-08 00:00:00 UTC)
! #expires 1609113600 (2020-12-28 00:00:00 UTC)
  
! #       Updated through IERS Bulletin C59
! #       File expires on:  28 December 2020