  We point out that results of Shimizu on internal characters imply a useful
non-semisimple variant of the categorical Verlinde formula for factorisable
finite tensor categories. When combined with results on pseudo-trace functions
by Miyamoto and Arike-Nagatomo, one can make a precise conjecture for a
non-semisimple modular Verlinde formula which relates modular properties of
pseudo-trace functions and the product in the Grothendieck ring of the
corresponding vertex operator algebra.
