The bosonic action functional of a quantum field theory with fermions is often not naturally given as a function on the space of field configurations, but a section of a line bundle. (See fermionic path integral). In the absence of a quantum anomaly this line bundle is trivializable. Any choice of trivialization makes the action functional an actual function. This choice is called sometimes the setting of the quantum integrand .
The quantum integrand of 11-dimensional supergravity is discussed in