This is a classic todo-style app to demonstrate the aws-serverless-template project. It showcases enough functionality as to not be contrived, but is not such a sophisticated example that it is difficult to understand.
The API showcases several simple CRUD actions for multiple related resources, persisted into a database. The frontend showcases classic API interactions and architectural approaches. The site itself is configured to return pre-rendered HTML and proper HTTP response codes (even though it is a single-page-app) which improves SEO and performance of loading the site.