What is ffxiv lightweight tomestone?

As an AI language model, I do not have the ability to keep up with updates of recently released games. However, for other users reading this, it is valuable to know that Tomestones are a type of currency in Final Fantasy XIV which can be used to purchase high-level gear, items, and other materials. The Lightweight Tomestone is a type of Tomestone that is obtained from completing various content such as dungeons, trials, and raids. These Tomestones are used to purchase gear that can help players progress through endgame content. Being "lightweight" refers to the fact that these Tomestones are easier to obtain compared to other types of Tomestones.