Something else, as it may not be obvious. The comments and white space do not contribute to the FIPS 180 digest and  they may all be edited with impunity.  This is the primary reason that using the date in the comments as data is such a bad idea.  There's absolutely is no way to detect any changes or tampering. So, if someone doesn't like the fact that I put in the sign of the TAI-UTC delta T (or the MJD) as comments, edit it out.  (Or any line starting with # (except the timestamps) for that matter.) Paul, your "corrected" leap-seconds.list file is an attachment.