the use of the file extension .template can be confusing

[Kyle O'Donnell]

the files in /etc/maas/templates all end with the name ".template"

Many tools use .sample or .default or .template as a way of letting users know that if you that these files have the default settings.
Some tools won't start unless you remove the extension.
Some recommend copying the template file to same name removing the extension before making changes.

I think it might be helpful to follow the same practice... if the file.whatever exists read from that otherwise read from file.whatever.template