Question about maxLevel

[siddhsql]

Hi,

In this code:

        Node(int id, MutableIntList[] connections, TItem item, boolean deleted) {
            this.id = id;
            this.connections = connections;
            this.item = item;
            this.deleted = deleted;
        }

        int maxLevel() {
            return this.connections.length - 1;
        }

why are you setting maxLevel to the number of connections (neighbors) of the node? The level of the node should be the layer number in which the node is stored. could you explain to me?

and what does this:

private MutableObjectIntMap<TId> lookup;

store? Is there any README explaining the data layout?