The NA message is sent in reply to NS messages.
The message is unicasted from the Globomantics router back to
the client between link‑local addresses,
as shown by the source and destination addresses.
The NA uses ICMP type 136 and code 0,
so it is a completely different type than the NS.
Notice that there are three flags.
I'll explain each one briefly.
The Router flag is Set when the device originating the NA is a router,
which is true in our case.
The Solicited flag is Set when this NA is in reply to an NS,
that is to say we didn't just announce an NA on our own.
Such an announcement is possible and is similar to an IPv4 gratuitous ARP,
and some devices send one right after DAD completes.
In this case, the bit is set because the NA was sent in reply to an NS.
The Override flag tells the receiver of the NA to overwrite any
existing entries in their ND cache with this new IP MAC binding
if they already had something stored.
This can be useful when network information changes and
overriding stale state on ND peers is important.
In this case, the bit is set, enabling the override.
The target address is the responder's link‑local address,
again, used to marry up the NS with the NA on the client.
The real meat of this NA message is in the ICMPv6 Option field,
which contains a target MAC address set to the router's MAC address.
This is the main question the NS was trying to answer, and now the client is able to send traffic towards the router.