The nature of the Holy Grail

My mother-in-law sent me recently a link to an article about the Holy Grail. Back in another life, I used to be an academic and a medievalist at that, specialized in the Arthurian legend and the work of Chrétien de Troyes, who was the first to introduce the Grail in Le Conte du Graal. It remains to this day my favourite Arthurian romance. In the story, the Grail is not a cup like in subsequent versions and the many adaptations, but a plate or a bowl, to contain large amount of food. While it is mentioned that a wafer is in it, so there are associations with the Eucharist, there is no explicit association with Jesus's death and his blood. Its origins remain obscure, as well as its ultimate purpose. Perceval/Percival does not ask the question that could potentially reveal its nature: "Whom does the grail serve?" The romance being unfinished, we will never truly know about its core subject, the rest is pure speculations. My bet, and I might be wrong, is that what the Holy Grail is was never meant to be revealed. It was meant as a MacGuffin: it makes the story flow, it creates tensions and motivations for the character, but otherwise we do not know because we do not need to know. Moral of this post: sometimes I miss academia.