I'm not sure whether it's what they meant, but I could see the "admin" cms portion being hosted on lambda.
You'd load a static editor page, write your content, and then post it to a lambda endpoint. That lambda would then generate static pages for your content and push it to s3 or wherever.
You'd load a static editor page, write your content, and then post it to a lambda endpoint. That lambda would then generate static pages for your content and push it to s3 or wherever.