Drinfeld modular rational cuspidal torsion conjecture

Let $\mathbb{F}_q$ be a finite field, let $\mathcal{A}=\mathbb{F}_q[T]$, and let $K=\mathbb{F}_q(T)$. For a monic $\mathfrak{n}\in\mathcal{A}$, let $X_0(\mathfrak{n})$ be the Drinfeld modular curve over $K$, let $J_0(\mathfrak{n})$ be its Jacobian, let $\mathcal{C}_{\mathfrak{n}}$ be the cuspidal subgroup, and let $\mathcal{C}_{\mathfrak{n}}(K)=\mathcal{C}_{\mathfrak{n}}\cap J_0(\mathfrak{n})(K)$. Let $\mathcal{C}(\mathfrak{n})$ be the rational cuspidal divisor class group, consisting of classes of $K$-rational divisors fixed by the absolute Galois group of $K$. Drinfeld modular rational cuspidal torsion conjecture. For every monic $\mathfrak{n}\in\mathcal{A}$,

$$\mathcal{C}(\mathfrak{n})=\mathcal{C}_{\mathfrak{n}}(K)=J_0(\mathfrak{n})(K)_{\operatorname{tors}}.$$

The inclusions $\mathcal{C}(\mathfrak{n})\subseteq\mathcal{C}_{\mathfrak{n}}(K)\subseteq J_0(\mathfrak{n})(K)_{\operatorname{tors}}$ are established in the context, and this conjecture predicts equality throughout. Its resolution is not specified in the supplied source.