The DevSecOps Iceberg was coined in this (https://wott.io/blog/thoughts/2019/11/29/the-devsecops-iceberg) blog post and speaks about the various layers (application, container, operating system) in your stack and infrastructure that needs to be protected. The relevant code, along with a PDF of the above deck (with working links) can be found here (https://github.com/vpetersson/cloudnative-london-demo).