if /MAP gives me a tree with branches, what is purpose of leaves then and why are they hidden ?

Hmm, I've never heard of the /leaves command, but judging from the word, I should imagine it shows the 'leaf' servers that are connected to the network in some form. Leaf servers are ones that are connected to the HUB servers, and usually what clients (i.e. me and you) connect to to connect to the network. Clients cannot really connect to HUB servers directly.

Regards,

you missunderstud

i just wanted to know why on /MAP leaves (leafs) arent shown (why are they hidden on any network) and what is their purpose ?

On many networks /map is restricted entirely. Similar commands that can determine connectivity are also often restricted. This is so an attacker can not easily determine which server to attack to cause the most damage. I would guess the leaf servers are hidden so the attacker can not do as much damage if he dislikes a certain client server/someone on that server. That makes little sense though as the hub servers would seem more 'vital' in terms of keeping the network connected. You can only ask the administration of that network as to their reasoning.

Hope that helps