From the back of the book:
Module G3A: Supplementary Annexes includes additional annexes with key daya covering the entire Alpha Octant, completely updated and in some cases entirely new.
Table of Contents: Covering the entire Star Fleet Battles game system for the Alpha Octant.
Annex #5 Abbreviations: An updated and complete list of all those codenames and pesky acronyms.
Carrier Escort Tables: AN entirely new annex never before available in printed form, this lists every carrier in the Alpha Octant and its ever-changing escort and fighter groups.
Master Scenario Index: Listing every ALpha Sector Star Fleet Battles scenario, including year, number of ships, which empires were involved, and special features. A secondary index allows players to access the Master Scenario Index by year.