The get_custom_field tag can be used to fetch the value contained within any editable region defined within any template.
It is an alternative method to using the pages tag and is well suited for fetching values from single fields (as opposed to the pages tag that fetches values of all the editable regions in a page).
<cms:get_custom_field 'site_name' masterpage='globals.php' />
The name of the editable region the value of which is to be fetched.
The name of the template that defines the editable region. This parameter is mandatory.
The name of the page that contains the editable region.
For non-clonable pages this parameter can be skipped.
<cms:get_custom_field var='content' masterpage='blog.php' page='my_test_page' />
This tag is self-closing and does not set any variables of its own.