@cwebber Hi! It seems you're knowledgeable about activitypub. I'm trying to learn about it, and I'm reading the w3c documents on activitypub, activitystreams and json-ld. I'd like to send a few requests manually to better understand the client-to-server protocol, but already am blocked: I don't understand how to find an actor object with only a username and server. I found my actor object: https://firstname.lastname@example.org but only by trying a few URLs. Can you help?