Using custom page template in custom Confluence blueprint plugin

[Craig Moran]

I am learning how to develop Confluence blueprint plugins.  I just finished the tutorial on this page: https://developer.atlassian.com/server/confluence/write-a-simple-confluence-blueprint-plugin/.  This tutorial shows you how to create an xml template and how to refer to it as a resource, in the atlassian-plugin.xml file.  Is there any way to use a custom page template -- the one that's in Confluence's database (PAGETEMPLATES) -- instead of an xml file?  Or, are we limited to just xml files?