If I understand it correctly (it looks like the jury is still out), a DevOp is someone who helps developers be more productive by giving them the tools they need.
As a freelance developer, from time to time I do some DevOp work, such as installing a library or some new software. Things can get quite complicated, but understanding how it all fits together, and knowing some tools and commands, can really speed things up.
Since I mainly use Linux Mint and Python, many of the DevOp articles on this website are about Linux Mint and Python. A lot of it will be relevant to other Linux distributions (distros) and languages.