[bobbyi_settv]

It generally means "ops work that is done with the best practices of dev work".

Yes, that means infrastructure as code, including code reviews, frequent deployments, etc.

No, it doesn't require that the developers working on the devops code are the same ones who work on the app code. At a small company (e.g., three devs) they will be, but at a large company, you have a dedicated "devops team" who exclusively works on infrastructure (as code).