Yes, they are.

They may be doing a poor job of it - time will tell.

But, at present, they're still the ones merging PRs and deploying changes to production.

It brings to mind the Chinese Room argument: https://en.wikipedia.org/wiki/Chinese_room

If a person in a Chinese Room doesn't actually understand Chinese, though the system as a whole behaves as if it does - can we say that the engineer merging PRs and deploying to production understands the system or maintains it?