Hi Ron,
yes, indeed, I had found the proper page, got a bit confused when I clicked the last link you posted and it got me a blank screen. But no worries: my screen dumps show that I indeed had found the demonstration page - and, alas, it does not work on my system.
Does my target audience use CentOS? Well, it depends on the course / LO. When one writes courses for the information security professional, or folks that manage cloud computing infrastructures, it is quite common to see them use some Linux variant. CentOS is a commonly used option for folks that don't want to pay a lot of money to Red Hat and still benefit from the Open Source software that they employ, so, yes, it happens.
Actually, I should not really have to bother, methinks. One of the main reasons to use Xerte for my projects is that it promised to render device independent LO's. Hence I expected it to run on (almost) all modern devices, like mobile phones (either Apple or Android based), tablets (ditto), desktops and laptops, running MacOS, Linux (at least the common stuff like Red Hat / CentOS, Ubuntu / Debian and SUSE) or even Microsoft (in it's various incarnations). Much depends on the browser of course, but I feel that Xerte should render correctly in Edge, Firefox and Chrome. Current versions.
I appreciate that much depends on the implementation of standards on these platforms and that there can be a number of issues, no matter how hard we try. For example, on some of my LO's I had to block out the accessibility options as they can mess up the presentation of the LO and confuse the learner. In itself a pity, as such options are very useful. I try to refrain from overly hacking the system, but in some cases I will merrily solve my problems myself, for example when the PDF stuff does not work on my platform: I have shared the information here how I solved my problems, so others can do likewise.
That's not to say that I would not welcome an out-of-the-box working solution that works on "all" systems, of course.