Leap seconds are planned to go away by the year 2035.

diff --git a/doc/misc/calc.texi b/doc/misc/calc.texi
index 89a340e73435ce66c3c0138019f8e68f4a7fffca..ef9990c057ae209eb75d8f059754592e213509ad 100644 (file)
--- a/doc/misc/calc.texi
+++ b/doc/misc/calc.texi
@@ -11040,7 +11040,8 @@ the year even for older dates.   The customizable variable
 have Calc's date forms switch from the Julian to Gregorian calendar at
 any specified date.
 
-Today's timekeepers introduce an occasional ``leap second''.
+A few platforms support leap seconds, such as the time stamp
+1972-06-30 23:59:60 UTC, an extra second appended to June 1972.
 These do not occur regularly and Calc does not take these minor
 effects into account.  (If it did, it would have to report a
 non-integer number of days between, say,