I think your definition of "sysadmin issues" is probably a little more limited than mine or 'wpietri's. I've had frontend developers insist that they could bake configuration settings into their webpacked artifact...which needed to be deployed into multiple environments because of course we weren't rebuilding something that had already been okayed in QA when we wanted to send it to prod.
You might say that's not a "sysadmin issue," but I have seen it happen three or four times now and in each case it was the "sysadmin" (read: devops engineer) who caught the problem and explained it to the offenders in question. (Maybe it's a "build engineer issue"...but at most companies I've seen, he or she is probably the "sysadmin", too.)
I would consider that sort of thing to be part of the required basic knowledge to be a competent frontend dev, so if you want to call that sys admin, then sure, there's a bit of it involved. If it's on your side of the fence then yes, it's your responsibility. I'm not sure how many actual sys admins would consider configuring webpack to be 'sys admin knowledge', but there is a spectrum and it's true that there are some ABCs that everyone needs to know, particularly when there are security implications. Still, it's a pretty far cry from unix, web servers, and databases.
You might consider it basic. I would have, insofar as I considered it pretty obvious even when I hadn't written a line of frontend code in five years, and webpack etc. weren't even on my radar then. ;) But my experience has led me to believe that it's not.
I think that's kind of the point of devops, though, is that something like a build system is a cross-cutting concern, that architectural decisions for an application need to involve people across the stack. Classifying somebody as "a sysadmin" is the problem in the first place, which is why I caveated my post as heavily as I did. My experience is that your "devops" or "sysadmin" people functionally become the "junk drawer programmer" who are relied upon for all sorts of weird stuff. I've been at jobs (and at clients) where I had to teach senior backend devs how to use VisualVM or what the implications of using Kafka and CQRS are. I've been at gigs like the aforementioned where I had to explain the ramifications of webpack to people knowledgeable and capable enough to make React dance. And so my definition is probably necessarily more broad...but it's also stuff I've had to do in practice, so, enh.
And, 'cause fair is fair, I think a "sysadmin" who couldn't step in and write production-quality code (allowing for a little ramp-up) is probably an endangered species over the next ten years, too.
You might say that's not a "sysadmin issue," but I have seen it happen three or four times now and in each case it was the "sysadmin" (read: devops engineer) who caught the problem and explained it to the offenders in question. (Maybe it's a "build engineer issue"...but at most companies I've seen, he or she is probably the "sysadmin", too.)