Project summary, including supported XEPs in a machine-readable format,
for automated listings, aggregation of XEP implementation status and
other nice things.
See https://xmpp.org/extensions/xep-0453.html
This list was simply scraped from the README and mangled into XML using
`csv2 | sed | 2xml` and amended with a few other details from e.g.
package.json and links on the website.
