Paul Eggert said:

Should TZif leap-second tables have no expiration date if leap seconds are discontinued, as draft -09 suggests? Or should they have an expiration date of (say) January 2100, which is likely a lower bound on the date that the leap-second regime would be replaced by some other regime, such as leap minutes? Or should we do something else about TZif leap-second expiry after leap seconds are discontinued?

I suggest waiting. Everybody else is going to have the same problem. As part of working out the no-leap details, somebody will have to pick a value so they can say something like "we won't have any leaps for the next N years". Then you can plug that number in. -- These are my opinions. I hate spam.