django - Why Python pytz package has both Asia/Kolkata and Asia/Calcutta timezones?

Question

This question already has an answer here: question from:https://stackoverflow.com/questions/65830519/why-python-pytz-package-has-both-asia-kolkata-and-asia-calcutta-timezones

Answer 1

From here:

Oh, I remember this. Asia/Calcutta was used in the tz database until several years ago. Now, Asia/Kolkata replaces this and Asia/Calcutta is in backward file. ICU/CLDR has "stable" ID policy - so ICU/CLDR still uses "Asia/Calcutta" as a "canonical time zone ID" and "Asia/Kolkata" as an alias. So, in ICU, both Asia/Calcutta and Asia/Kolkata work fine - but when you try to get canonical ID via API, it will be "Asia/Calcutta", instead of "Asia/Kolkata"

So it is an alias and not an obsolete name.

It is actually a duplicate of this one