I wasn’t doing a lot of “ops” type stuff at the time but I get the impression that a few years ago some people were using the term to mean “you build it, you run it”, without necessarily requiring as much tooling and infrastructure as seems to be expected today.

Modern devops == configuration management, CI tools, and expectation that you at least take an interest in containerisation.

(I tend to feel that, at least until you get to quite a large scale, there’s still a fair amount of value in “developers who aren’t scared to poke production servers when needed”, but it doesn’t really seem accepted to use the word “devops” to describe that kind of setup.)

Not ancient, I suppose :)

Yeah, but what about the other word from the term? It's not well-defined and its definition varies vastly from person to person.

I think the downvotes are not earned here -- devops as a way to work is relatively new, so one could say all of it is modern. That's where the question is probably headed.