[TomTom]

The position data calculates as float little endian. Here is the node sub struct I have figured (followed by the variable-sized connection array, and eventually the actions and routes arrays-of-struct I guess.)

typedef struct  
 {     //stored as little endian
      //short Num;  //implied by index
      float x, y, z;   //z value is 40 below /viewpos when standing, 
                          //              8 above  /viewpos when prone,  
                          //  unaffected by node radius value
      short Flags;
      short EntNum;
      short number_of_Connects;
      short Radius;
      short Team;
      short Group;
 } s_fNode;

Still trying to figure if the 9th byte in the header is string terminating nul or a version digit...