A SSL/TLS session is a session between two applications that have successfully performed an SSL Handshake.
You can examine the connection and server certificate connection with portecle
With OpenSsl and the s_client command 1)
openssl s_client -connect host:443 -state -debug
At the end of the handshake, you can see the session info.
SSL-Session:
Protocol : TLSv1.3
Cipher : TLS_AES_256_GCM_SHA384
Session-ID: 38E38C70E914EA40D81C47E662EE477109A79F93362EB0BA9D7DB9BEF9F79A02
Session-ID-ctx:
Resumption PSK: 7A877BEAA39FC03077ACAC5D8F875E0D9C3942E9EC17FDEA19255AFCD8CC697323C217FF4AF6EAB65123FED80457D42E
PSK identity: None
PSK identity hint: None
SRP username: None
TLS session ticket lifetime hint: 14400 (seconds)
TLS session ticket:
0000 - 47 ea 4d 76 24 fa a9 01-08 85 5a 02 e2 f2 14 60 G.Mv$.....Z....`
0010 - 6a 51 cc e1 90 65 0c 22-6c 6b 0e 48 34 c0 34 5e jQ...e."lk.H4.4^
Start Time: 1647165467
Timeout : 7200 (sec)
Verify return code: 0 (ok)
Extended master secret: no
Max Early Data: 0