Reviewer: Qin Wu Review result: Has Nits I have reviewed this document as part of the Operational directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written with the intent of improving the operational aspects of the IETF drafts. Comments that are not addressed in last call may be included in AD reviews during the IESG review. Document editors and WG chairs should treat these comments just like any other last call comments. This document defines the Time Zone Information Format (TZif) for representing and exchanging time zone information. The typical application is iCalendar or scheduling system. This document is ready, and I only found a few nits in it. 1.Section 3, what is 32-bit transitions, what is 64 bit transitions, how it is different from 32-bit transition times and leap second occurrences, why header should also include 32 bit transitions? Wouldn’t header a 44-octet header? Would it be great to add transition as a new term in the terminology section. 2.Section 3.2 What is the header of the 64-bit data block, how it is different from 64bit transitions? Isn’t header of the 64 bit data block 44-octet header? 3.Leap second records definition How 64 bit data block can be used to accommodate 16 octet records? 4. Can you explain footer is needed for version 2 and 3 of TZif file while not needed for version 1?