Since the specifications of the Xwing Alliance opt file format was nowhere to be found on the web,
I have decided to make it available here for anyone that still finds an interest in it.
Thanks to those who have written the documents.

-isildur

Xwing Unofficial Specs - by StealthJedi

Alternative OPT File Reading - by 3DOXprt

Opt Files (in pdf) - by StealthJedi