The purpose of ISO 3166 is to define internationally recognised codes of letters and/or numbers that we can use when we refer to countries and subdivisions. However, it does not define the names of countries – this information comes from United Nations sources (Terminology Bulletin Country Names and the Country and Region Codes for Statistical Use maintained by the United Nations Statistics Divisions).
However, in the "United Nations Group of Experts on Geographical Names" I see this mentioned,
The most recent list of country names approved by the Working Group was submitted on behalf of UNGEGN for the Eleventh UN Conference on the Standardization of Geographical Names in August 2017. It is available as E/CONF.105/13.
But in E/CONF.105/13 I don't see them define Palestine anywhere. How did it and others get into ISO 3166? Where is the authoritative source for the names in ISO 3166 -- is it the standard, the ISO Working Group, or the UN? And who standardizes the translations?