Your server knows to send tune information to Romeo because when the server unpacks the value of the 'ver' attribute ("054H4A7280JuT6+IroVYxgCAjZo=") in accordance with XEP-0115, it discovers that Romeo's client advertises a service discovery feature of "http://jabber.org/protocol/tune+notify", where the "+notify" suffix indicates interest in receiving notifications related to the protocol that precedes the suffix. The server can verify this support if needed by sending a service discovery request to Romeo's full JID, where the response would be as follows:
+Your server knows to send tune information to Romeo because when the server unpacks the value of the 'ver' attribute ("054H4A7280JuT6+IroVYxgCAjZo=") in accordance with XEP-0115, it discovers that Romeo's client advertises a service discovery feature of "http://jabber.org/protocol/tune+notify", where the "+notify" suffix indicates interest in receiving notifications of the node whose NodeID precedes the suffix (see XEP-0060 ยง 9.2). The server can verify this support if needed by sending a service discovery request to Romeo's full JID, where the response would be as follows: