Is there a reliable way to get the RSS feed for a hugo site

I am new to hugo. It seems to me that I can get RSS feed from index.xml under the root directory. Can I depends on that for other people’s hugo sites? Also, I observed that many blog like sites have:
<link rel="alternate" type="application/rss+xml" href="index.xml">
in the generated index.html, so it is relatively easy to figure out the correct rss feed programmatically. However, some site has it, some doesn’t. This is probably a template issue.

The reason I want to ask is I want to write a tool to derive the RSS link through heuristics so one can easily subscribe in a feed aggregator. Hugo is very popular and the RSS functionality is built right in; it would be nice to have consistent and easy rules to do what I want.

The reliable way is to read the link element to find the feed a site publisher is publishing.

In Hugo the RSS output can be customized.

You mean <link rel="alternate" ...>, right? However, some hugo sites in the wild do not have it, yet still have index.xml.