This module is the building blocks for the AWS CodeBuild projects. It has the foundational pieces for using codebuild to build Linux software / RPMs. You may need to compile an RPM for a specific release of an OS, and CodeBuild by default only has Docker images for Amazon Linux 2 and Ubuntu. So part of this builds RHEL Docker images so that you can compile software in a RHEL userspace.
It builds these resources:
docker build
containers for the OS-specific containers
The ECR repo and related codebuild jobs use a submodule. The OS-specific containers are rebuilt daily to keep them up to date with the latest RHEL patches.