Continuing the discussion from Links not working:
New user manual page link is now:
https://frappe.github.io/erpnext/user/manual/en/customize-erpnext/customize-form.html
The link that is not working is:
https://kb.frappe.io/kb/customization/form-architecture
which redirects to:
https://frappe.github.io/frappe/current/customization/form-architecture
which returns 404 