Moduli Spaces of (co)closed $\mathrm{G}_2$-structures on nilmanifolds

We compute the dimensions of the moduli spaces of left-invariant closed and coclosed $\mathrm{G}_2$-structures on 7-dimensional nilmanifolds, showing that they are not related to the third Betti number. We also prove that the group of automorphisms of a coclosed $\mathrm{G}_2$-structure is not abelian, in general.