Here, "fresh" means that the fresh-picked green tea leaves never go through a drying process at all. In other words, after green tea leaves are harvested, within about 4 hours or less, the green tea leaves are in the extraction process; just like fresh vegetables (You don't want to eat dry or processed vegetables!).
Because fresh green tea leaves can't be stored for a long period, almost all of commercially available green tea products including extracts and tea bags are made from dried green tea leaves. However, many tea companies including leading-brand tea companies try to confuse consumers by using words such as "fresh", "fresh brewed", or "natural tea leaves". No matter what kind of wording they use, it is clear that their green tea products are made from dry or processed green tea leaves.