If you have offices worldwide, it is useful to know which public holidays and subsequently, non-working days there are in each country.
Productive does this automatically. When you create a new subsidiary, Productive will ask you to assign it to a country:
Now, go to Settings > Holidays and add a holiday calendar for that country. You can also manually change holidays (as laws change, or in some countries, not all holidays are observed on the same day every year):
In Contacts > People, you can assign different holiday calendars to different people:
This is useful if you have teammates from different countries, and you can set those independently from the subsidiary.
For example, if you have a teammate that is remotely working in Canada but is employed in the US branch of the company, you can set their holiday calendar to observe Canadian holidays (and non-working days).