∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C] (B : C) {J : Type w}
  (F : CategoryTheory.Functor (CategoryTheory.Discrete J) (CategoryTheory.Over B))
  {X Y : CategoryTheory.Limits.Cone (CategoryTheory.Over.ConstructProducts.widePullbackDiagramOfDiagramOver B F)}
  (f : X ⟶ Y),
  ((CategoryTheory.Over.ConstructProducts.conesEquivFunctor B F).map f).hom = CategoryTheory.Over.homMk f.hom ⋯