The mean-field Ehrenfest (MFE) approach is a semiclassical, mixed quantum-classical dynamics approach that simultaneously evolves a quantum subsystem and a classical subsystem. Multiple classical trajectories are evolved such that their distribution through time can be tracked to estimate e.g. the time evolution of the probability density of the wavefunction that the classical subsystem is approximating. For the electronic-nuclear dynamics of molecules, the electrons (or electrons and photons) are treated quantum mechanically while the nuclei are treated classically such that the distribution of the classical nuclear trajectories estimates the probability density of the nuclear wavefunction through time. The trajectory average of the electronic wavefunction is used to compute quantum estimators such as the elements of the electronic density matrix.