I searched all UBS boards for "RSS Feed," but there were zero results.
99% of UBS information is posted at Area 51 (you've not logged into Area 51 since Jul 5, 2023). There is not that much information about UBS here yet as I just recently started selling public standard licenses for UBS and there are only a couple UBS Standard license holders, 99% of UBS license holders are Premium Licenses holders and they all use Area 51 for advanced/priority support.
With that said, All of my addons have the same types of RSS functionality as Core XenForo and XFMG (XFRM does not have RSS functionality). UBS has had RSS functionality since UBS 1.x for XF 1.x.
Pages like UBS Index, UBS Category and individual Blog pages are designed so that the controller detects if the viewing user is an RSS feed reader and will then render the view in RSS format vs human viewable format. This is the same exact way the Core XF and XFMG work (and again, XFRM does not have any RSS functionality in XF2, it did for XF1).
Keep in mind that RSS views are NOT meant for viewing by users, they are designed to be read by Feeder Readers, which is why the controller auto detects and sets the type of view automagically.
You can directly view a page in RSS format simply by appending index.rss to the end of the URL. I've appended index.rss to the UBS Index page URL, a UBS Category page URL and a UBS Blog page URL. You can cut and paste those to see those pages in RSS format.
Code:
UBS Index RSS Feed: https://demos.xenaddons.com/blogs/index.rss
UBS Category RSS Feed: https://demos.xenaddons.com/blogs/categories/breakfast.3/index.rss
UBS Blog RSS Feed: https://demos.xenaddons.com/blogs/blog/the-olde-zords-country-kitchen.1/index.rss
You can also easily check if a page has RSS Feed support or not by appending index.rss to the end of the page URL and if that page isn't designed to have an RSS Feed, it will show you this, which is telling you that the page you are viewing can not be rendered in RSS Feed Format. This URL is to the UBS Blog List, which is NOT designed to have an RSS feed.
As mentioned above, XenForo Resource Manager does not have any built in RSS functionality, so appending index.rss to any XFRM URLs is going to to tell you that the page can not be rendered in RSS format.
Most modern Feed Readers can auto detect, which is why you can just use the standard URL without needing to append index.rss to the end of it.
I don't see an RSS icon on the blog index, nor individual posts.
Nor do Core XF Forum Pages, XFMG Media Index, XFMG Media Albums, XFMG Media Categories. That is OLD SCHOOL and not needed as modern RSS Feeders are detected and presented the page in RSS format vs human viewable format IF the page supports an RSS feed.
When I click on the RSS icon on the footer, of course, it just does a forum feed.
That is the only place that Core XF displays an RSS Icon and is not a "FORUM" RSS, its more of a Latest Threads from ALL Forums. Individual Forums have their own RSS Feeds (simply view a forum and append index.rss and you will see that its only content fetched for that particular Forum, vs clicking on the RSS Icon which fetches lastest threads from all forums).
UBS also has RSS Feed Importer, which is similar to the Core XF RSS Feed Importer that creates threads from an external RSS Feed, except the UBS RSS Feed Importer creates Blog Entries from an External RSS Feed.