Reference https://www.packer.io/docs/commands/validate.html
The packer validate template.json command checks the specified Packer template file for syntax correctness and completeness. This command ensures that the template is properly structured and ready to be used for building images.
* Syntax Check: Verifies the JSON syntax of the template.
* Completeness Check: Ensures all required fields and configurations are present in the template.
References:
* Packer Documentation - validate