The RSS feed buttons are located all over the place.
On the main forum page https://forums.galciv2.com/ at the bottom of the page at there's a link for "More Recent Posts" and to the right margin of this is a RSS feed button that if you mouseover tells you it's the RSS for the last 10 recent posts.
If you go to the Recent Posts list https://forums.galciv2.com/recent then at the top right you'll see a RSS feed button that tells you it's the RSS for *all* Recent Posts.
Finally if from the main forum page you select an individual forum, say GalCiv II for example then at the top of the Pinned Posts section again on the right is RSS feed for the GalCiv II Pinned posts. If you scroll down further to the GalCiv II Recently Active Posts there's an RSS feed for those as well. The other forums are similar as well.
However what you can do with these and how you go about using them is an entirely different matter. A friend of mine did produce a "forum scraper" using the RSS feeds but a couple of things makes it less than ideal. One is that you need a server to "host" the code and the other is that what it actually produces is an html file containing links to the individual articles. It then seems that you access each article by clicking on each link but that opens up your browser separately for each article and there's no way to navigate normally within your browser from one article to the next, however, my understanding of this entire process is very limited so I could be completely wrong in my assumptions. I will also be very interested in seeing what kind of response you get or in hearing about any results you come up with.
My ideal situation would be to have what appears to me to be identical to the current forums only with some control as to what forums I could exclude from my view. I have no idea of how to get to that goal.