TKT is not heavily split in the current catalog, but the short label still hides the underlying IANA zone and any future policy change. The safe pattern is to write the abbreviation for humans and the zone for machines.
Pacific/Fakaofo sits at one of the far edges of the offset spectrum (+13:00). Pages and software that assume "close to UTC" often render TKT incorrectly, so explicit handling is more important here than on UTC-adjacent zones.
For precise work, the safest equivalent of TKT is the exact IANA zone used by your city or system. Pacific/Fakaofo sits at +13:00, ahead of UTC, which means daily logs in this zone reach a new calendar date before UTC does — a small detail that breaks date-based reporting if missed.
Within this single zone (Pacific/Fakaofo, +13:00), TKT is unambiguous, so the abbreviation and the IANA zone effectively interchange.