Chapter 9

1. The rendered template is returned in the JSON format.
2. It is either a piece of a template or a full template, depending on whether the Transform section is declared or the Fn::Transform function is used.
3. The stack operation will be considered as Failed, and CloudFormation will start rolling back.
4. Yes, but you need to be aware of the macro evaluation order: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/template-macros.html#template-macros-use.
5. No. At the moment of this writing, CloudFormation module extensions do not support any macros, including language extensions.