1 files changed, 4 insertions, 0 deletions
diff --git a/leapseconds.awk b/leapseconds.awk
index 1d3c606..b6c48bc 100755
--- a/leapseconds.awk
+++ b/leapseconds.awk
@@ -24,6 +24,10 @@ BEGIN {
   print "# NIST format leap-seconds.list file, which can be copied from"
   print "# <ftp://ftp.nist.gov/pub/time/leap-seconds.list>"
   print "# or <ftp://ftp.boulder.nist.gov/pub/time/leap-seconds.list>."
+  print "# The NIST file is used instead of its IERS upstream counterpart"
+  print "# <https://hpiers.obspm.fr/iers/bul/bulc/ntp/leap-seconds.list>"
+  print "# because under US law the NIST file is public domain"
+  print "# whereas the IERS file's copyright and license status is unclear."
   print "# For more about leap-seconds.list, please see"
   print "# The NTP Timescale and Leap Seconds"
   print "# <https://www.eecis.udel.edu/~mills/leap.html>."