Aeon's End Insert: - Rules of Play says:
Insert compatible with Aeon's End®, and includes space for numerous expansions, storing 840 sleeved or 1,300 unsleeved cards. Insert is also compatible with the Aeon's End: War Eternal® and Aeon's End: The New Age® games. The design provides both efficient storage and improved game play. Many of the trays can be utilised during the game, and they greatly aid set-up and clear-away times. The rules act as a lid on top of the trays.