UoM in Item Purchase Details

In the User Manual, here, the last screenshot on the page shows UoM Conversion under the Purchase Details section on the Item master. This doesn’t appear on my system:

Installed Apps

ERPNext: v9.2.17 (master)

Frappe Framework: v9.2.18 (master)

How do I get those details to appear? How do they differ, functionally, from UoM details which appear under their own heading?

You will find it in the Item DocType, attaching a screenshot below.

Thanks for your reply.
Are you saying that the documentation is out of date, and the UoM was moved from the Purchase detail heading to its own heading?

Yes, that’s right.