  When discussing the gauge symmetries of any theory, the Henneaux-Teitelboim
transformations are often underappreciated or even completely ignored, due to
their on-shell triviality. Nevertheless, these gauge transformations play an
important role in understanding the structure of the full gauge symmetry group
of any theory, especially regarding the subgroup of diffeomorphisms. We give a
review of the Henneaux-Teitelboim transformations and the resulting gauge group
in the general case, and then discuss its role in the applications to the class
of topological theories called nBF models, relevant for the constructions of
higher gauge theories and quantum gravity.
