Print Format Field Template

Frappe Framework App Development
,
1

I have seen core doctype " Print Format Field Template". Couldn’t find any documentation on that

1.) How to use this?
2.) is that work only with new print format builder or also old builder?

2

Still not to be found in the documentation at https://docs.frappe.io/erpnext/, still only lots of false positives.

The UI of the form for this DT also lacks any hints.

What are these Print Format Field Templates used / useable for?