Notation in Siu's paper

Question

In the following paper of Siu Yum-Tong:https://www.ams.org/journals/proc/1967-018-05/S0002-9939-1967-0216032-3/S0002-9939-1967-0216032-3.pdf, which he proved that Cartan B implies A, he used the notation $\mathfrak{J}\mathfrak{F}$, where the first is a sheaf of germs of holomorphic functions vanishing at some point $x\in X$, where $X$ is Stein, and $\mathfrak{F}$ is a coherent analytic sheaf on $X$. What could he possibly mean by this notation. It doesn't seem standard as I have never seen this before.