Smbtree output, hostname?

Just playing about with Samba today, if I run smbtree on a couple of clients I get:

WORKGROUP
HOME
    \\P_151                  Samba 4.5.12-Debian
        \\P_151\IPC$               IPC Service (Samba 4.5.12-Debian)
        \\P_151\Share              Pi Share
        \\P_151\print$             Printer Drivers

What is P_151 ? Is it meant to be the host name? If it is it's very incorrect and very incorrect on all my clients.

My clients run on sd cards, this 'might' have been the name when samba was first installed, but the sds are duplicated and the hostname changes later.

So, if this is the hostname, what files do I need to be changing?

Many thanks.

SERIOUSLY: Make absolutely sure you apply the necessary code tags to data to preserve the structure / indentation that helps interpret what is being shown!

What you ask about is the normal output of smbtree for a HOME workgroup / domain to which the server P_151 with three (default?) shares belongs.

man smbtree :