  I report on the first application of a novel, generalized Bayesian
reconstruction (BR) method for spectral functions to the characterization of
QCD constituents. These spectral functions find applications in off-shell
kinetics of the quark-gluon plasma and in calculations of transport
coefficients. The new BR method is applied to Euclidean propagator data,
obtained in Landau gauge on lattices with $N_f=2+1+1$ dynamical flavors by the
"twisted mass at finite temperature" (tmfT) collaboration. The deployed
reconstruction method is designed for spectral functions that can exhibit
positivity violation (opposed to that of hadronic bound states). The
transversal and longitudinal gluon spectral functions show a robust structure
composed of quasiparticle peak and a negative trough. Characteristic
differences between the hadronic and the plasma phase and between the two
channels become visible. We obtain the temperature dependence of the
transversal and longitudinal gluon masses.
