gnu-social/socialfy-another-domain/dot-well-known/host-meta

<?xml version="1.0" encoding="UTF-8"?>
<XRD xmlns="http://docs.oasis-open.org/ns/xri/xrd-1.0" xmlns:hm="http://host-meta.net/xrd/1.0">  
 <Link rel="lrdd" type="application/xrd+xml"
        template="https://example.com/.well-known/webfinger?resource={uri}"/>
</XRD>