I honestly dont know because I cant even open it. But the old format was something like this:
FFFF: GG HHHHHHHHHHHH : JJJ (XXX YYY ZZZ) KK LL MM NN ...
F = object ID number,
G = object type ID number,
H = object type filename,
J = object heading
X = object latitude
Y = object altitude
Z = object longitude
K,L,M,N... = all unknown stuff
Each line was an object placement. To add a new object, you would just make a new line, then resave it using a special tool that would re-inject the data. But that tool no longer works since FC2. So the format probably changed.
Not sure if this helps or just made things more confusing...