The UTC+14 time zone used by Kiritimati is Line Islands Time.
Line Islands Time, abbreviated LINT, is 14 hours ahead of Coordinated Universal Time. It is used in Kiribati's Line Islands, including Kiritimati, also called Christmas Island. Because the zone is so far ahead of UTC, Kiritimati is among the first inhabited places to reach January 1 each year.
Kiribati moved the International Date Line around its eastern islands in 1994. Before that change, the country's island groups could be separated by different calendar dates despite belonging to the same nation. The adjustment placed the Line Islands on the same side of the date line as the rest of Kiribati.
Kiritimati is not the first land anywhere to see a new day in every geographic sense, because uninhabited areas and different definitions of “first” complicate the claim. The precise fact is that it uses UTC+14 and is one of the earliest inhabited locations to celebrate New Year.