DevOps grew out of a reaction against the wall between developers who write the code and operations who look after it. In practice the team owns the automation, observability, on-call and infrastructure around its own service — not the whole cloud platform, just its part. Where the line between “our part” and “someone else’s” is drawn is one of the most important design decisions an organisation makes. The phrase “you build it, you run it” comes from Amazon CTO Werner Vogels in an interview in ACM Queue.
DevOps is often confused with delivery engineering, since both live in pipelines. The difference is that DevOps tells you how to share responsibility, while delivery engineering tells you how to share the tooling — we have written more about it in Delivery Engineering vs. DevOps (in Swedish). How well the way of working holds up can be followed with the DORA metrics.