Before revision:  We find that the cell deformation and cell rearrangement rate fields correlate strongly, which is compatible with a  viscoelastic liquid behaviour with a relaxation time \tau = 70 \pm 15 min.
After revision:  We find that the cell deformation and cell rearrangement rate fields correlate strongly, which is compatible with a viscoelastic liquid behaviour (and not with a Kelvin-Voigt viscoelastic solid behaviour). The value of the associated relaxation time is measured as \tau = 70 \pm 15 min.