A Terrain map existed before global but got removed.
The Terrain map would be useful for approaches in Mountainous areas or for radar vectors to airports surrounded by high terrain
The terrain map was removed due to performance issues with the Global update. They will (hopefully) add it back once they find a workaround for the issues.
The FDS team have already stated that they may implement the map at a later date, however there would be serious performance issues for all devices. This is about the 5th time I’ve seen a request about this…