I am working on an investigation on TLS 1.3. I've came across an article of qacafe where they shared a TLS 1.3 handshake sequence. Wireshark capture. In this capture you see that in the Client Hello a key_share is being send where it is "guessing" which cypher suite to use. This saves some bytes. by not having to send the whole list. However I don't see any certificate exchange in this capture.
Does someone know why the certificate exchange is missing here? An reason could be the pre_shared_key method of TLS 1.3, however I don't see that extension being used in the Client Hello. Does someone have an explanation for this?