Taiwanese language and country codes

Question

I'm a bit uncertain between the two variations below:
zh-cht and zh-tw - it's for a site in traditional Chinese, mostly in Taiwan, but presence in Maccao and Hong Kong.

So zh-cht and zh-tw seem to represent the same language.
Possibly their are vernacular differences?
But zh-cht - seems to be an umbrella for the various vernacular differences?

If I try to compare to Spanish, it's difficult as it seems Spanish has less recent geopolitical upheavals.

I.e. es-co - is Spanish in Colombia but no one has to worry about whether we are speaking of "Grand Colombia - which would include Ecuador and Venezuela" that geopolitical issue is so far behind us, you know, they are now different countries officially and have been for a long time, so their's no issue so we all know es-co - refers to the country of Colombia and the fairly individual dialect they speak. No? Their is (googling this more) ES-419 which covers a range of Spanish's which is used to describe spanish of Latin America and the Carribean.

So how does this apply to zh-tw and zh-cht? Is zh-cht the ES-419 of traditional Chinese?

Answer 1

In case it's useful: zh-Hant is the correct code.

https://www.w3.org/International/articles/language-tags/ (Thank you andrewJames)

Answer 2

I'm from Taiwan, and I stumbled upon this somewhat old question. "cht" corresponds to the English abbreviation for "Traditional Chinese," and "tw" corresponds to the region of Taiwan. I won't delve into too many geopolitical topics here, but in essence, Taiwan is the only place in the world where Traditional Chinese is officially used, making the two terms essentially interchangeable.

Regarding BCP-47, they correspond to different versions of BCP-47. I believe choosing one aligned with other language codes would suffice. Many places still use ISO 639-1 (I do too), so it should be "zh-TW."

If you're using an updated version of BCP-47, please refer to another answer.