Thanks to Dr. Levine, NIST has a newer version of leap-seconds.list with an expiry of 28 Dec 2019.  Hurrah!!  (Note: I re-named it so I could see the different versions.) $ FIPS180 -f NIST_leap-seconds.3676924800.2019-01-31 -v -h         Generated SHA digest matches file digest             File name: NIST_leap-seconds.3676924800.2019-01-3 Original file name: leap-seconds.3676924800      Last modified: 31 Jan 2019 08:02:47 UTC            Updated: 08 Jul 2016 00:00:00 UTC            Expires: 28 Dec 2019 00:00:00 UTC #h      83c68138 d3650221 07dbbbcd 11fcc859 ced1106a $