Resolving issues with the RSS feed

I am seeing issues with the RSS feed.

https://www.swift.org/atom.xml

Validtion using validator.w3.org provides the following reccomendations:
https://validator.w3.org/feed/check.cgi?url=https%3A%2F%2Fwww.swift.org%2Fatom.xml

## Recommendations

This feed is valid, but interoperability with the widest range of feed readers could be improved by implementing the following recommendations.

* Your feed appears to be encoded as "utf-8", but your server is reporting "US-ASCII" [[help](https://validator.w3.org/feed/docs/warning/EncodingMismatch.html)]

* [line 4](https://validator.w3.org/feed/check.cgi?url=https%3A%2F%2Fwww.swift.org%2Fatom.xml#l4), column 82: Self reference doesn't match document location [[help](https://validator.w3.org/feed/docs/warning/SelfDoesntMatchLocation.html)]
> ... https://swift.org/atom.xml" rel="self"/>
> ^

* [line 3077](https://validator.w3.org/feed/check.cgi?url=https%3A%2F%2Fwww.swift.org%2Fatom.xml#l3077), column 0: content should not contain style tag (2 occurrences) [[help](https://validator.w3.org/feed/docs/warning/SecurityRisk.html)]
> <id>https://swift.org/blog/dictionary-and-set-improvements/</id>

* [line 11333](https://validator.w3.org/feed/check.cgi?url=https%3A%2F%2Fwww.swift.org%2Fatom.xml#l11333), column 0: style attribute contains potentially dangerous content: `img { max-width: 100%; height: auto; }` (3 occurrences) [[help](https://validator.w3.org/feed/docs/warning/DangerousStyleAttr.html)]
> <id>https://swift.org/blog/swift-5.3-released/</id>

When attempting to fetch the feed using node.js package rss-parser, I get the following error:

Error fetching feeds: Error: Non-whitespace before first tag.

I believe the most likely culprit is the first recommended fix by w3's validator. Ensuring the server is reporting utf-8

We have seen issues similar in the past:

3 Likes

Your feed appears to be encoded as "utf-8", but your server is reporting "US-ASCII"

https://github.com/apple/swift-org-website/issues


Self reference doesn't match document location

https://github.com/apple/swift-org-website/blob/main/_config.yml

Should the Jekyll configuration be updated?

-url: https://swift.org
+url: https://www.swift.org

content should not contain style tag

style attribute contains potentially dangerous content

https://github.com/apple/swift-org-website/blob/main/atom.xml

It's possible to use a plain-text <summary> instead of the <content> element.

The jekyll-feed generator plugin isn't used, but it shows how to filter a post excerpt.