Add a Feed of the Upcoming Events page

[dd32]

Spurred by #1559 and a desire to have Events notifications in other places, it got me thinking about using RSS feeds.

This PR implements RSS feeds for urls such as:

• https://events.wordpress.org/upcoming-events/
• https://events.wordpress.org/upcoming-events/filtered/country/AU/
  The feed url is suffixing /feed/ to those URLs.

Some shortcomings were encountered:

• The current event query code doesn't return the description, and always queries for 500 elements. Allow Event query to return the event description, and limit wporg-mu-plugins#713 (This is a precursor to this feed PR)
• RSS doesn't seem to handle future-dated content very well.. if at all.. as this is explicitly not allowed by the spec really
• As the date isn't deemed valid by some clients, the order of the items in the feed is somewhat not predictable

Not implemented:

• Page headers and links to the RSS feed to make it visible.
• Feed Title is <title>Posts filtered by: Australia &#8211; WordPress Events</title> which could do with changing to Upcoming Events filtered by:

Screenshots

Example of a RSS reader, as you can see, the event order is December 2025, Jan 2026, Dec 2025, Nov 2025 despite the feed being ordered as Nov, Dec, Dec, Jan.

[dd32]

RSS doesn't seem to handle future-dated content very well.. if at all.. as this is explicitly not allowed by the spec really

Atom feeds might help here, we can set pubDate to when we're first aware of an event (which annoyingly we don't store), and Updated to the date of when the event occurs.. it seems that some clients handle future dates in the updated field.