Hi! Oh, no, webmention.io isn’t involved at all. You’re right that the target https://fed.brid.gy/ , and the endpoint is https://fed.brid.gy/webmention , which you can find by doing endpoint discovery: https://www.w3.org/TR/webmention/#sender-discovers-receiver-webmention-endpoint
@snarfed.org Ok, thanks. That is working now.