An RSS feed is used by news aggregator tools (like Apple News) to assemble a list of recent news posts tailored to the user's interests. The feed lists the most recent posts in XML for use by those tools. The yellow RSS icon on the sidebar is a link to the feed. Clicking it sends the feed to the user's news reader application, if any (such as Apple News).
RSS feeds can be a good way to promote new features, news, etc. We could use this to announce newly published datasets.
... interesting ...