  The Witten-Sakai-Sugimoto model, a top-down gauge/gravity model of
large-$N_c$ low-energy QCD based on type-IIA string theory and $N_c$ D4 branes
with chiral quarks added by probe D8 branes, involves only one dimensionless
parameter, the 't Hooft coupling at its cutoff (Kaluza-Klein) scale. Although
this cutoff scale is around 1 GeV, the model has turned out to be surprisingly
predictive also quantitatively, reproducing masses of vector and axial vector
mesons, their decay rates, as well as the anomalous mass of the \eta' meson,
all within 10-30% errors. Using it as a guide for glueball signatures, we have
argued that it indicates that the meson $f_0(1710)$ may be a nearly pure
glueball, with rather specific predictions for the still-to-be-measured 4\pi
and \eta\eta' decays. Here we present our new predictions for the decay pattern
of the (very narrow) pseudoscalar glueball, which is closely related to the
U(1)$_A$ problem that the model is in fact handling correctly.
