Hey, soon you can ask nbuild.io chatbot. I launched a ui preview on nbuild.io and nbuild.io/answers. I asked the chatbot your question. I received this answer:

Extra kind 0 profile fields are mentioned in NIP-24 https://github.com/nostr-protocol/nips/blob/master/24.md

And NIP-39 mentions external profiles such as social media links. https://github.com/nostr-protocol/nips/blob/master/39.md

Would you do me a favor and let me know if this is the answer you are looking for?

Will launch the chatbot next week.