Gabber's torsion-freeness conjecture for punctured spectra

Let $(R,\mathfrak{m})$ be a local complete intersection ring of dimension $3$. Let

$$U_R=\operatorname{Spec}(R)-\{\mathfrak{m}\}$$

be the punctured spectrum of $R$. Gabber's conjecture. The group $\operatorname{Pic}(U_R)$ is torsion-free. The paper notes that its positive-characteristic case follows from the theorem proved there; the conjecture is attributed to Gabber and concerns the absence of torsion in Picard groups of punctured spectra of three-dimensional local complete intersections.