Field type "Duration" not available

In the ERPNext Documentation it says there is a field type “Duration” (at the very bottom of the page)
https://docs.erpnext.com/docs/user/manual/en/customize-erpnext/articles/field-types.html

I am currently on
ERPNext: v12.8.0 (version-12)
Frappe Framework: v12.5.2 (version-12)

but I am unable to find the duration field type in my DocTypes

Any suggestions?

I believe it’s in development right now, and will soon be available. If you want to, you can go ahead and pull the PR to your local instance from this: feat: Duration Control by ruchamahabal · Pull Request #10248 · frappe/frappe · GitHub