Platform & DevOps·Packaging: containers and images
an image built by one tool runs under a different runtime on someone else's cluster, and nobody had to agree on a vendor.
Open Container Initiative
Also calledOCI, OCI spec, OCI image format
The specifications that define what a container image, a runtime and a distribution registry are, independently of any product. It is why 'Docker image' and 'container image' have become the same thing in practice, and why the build tool, the registry and the runtime in your stack are probably three different projects. It matters most when it is absent — a format outside the spec is a lock-in you find out about at migration time.