  To understand typical dynamics of an open quantum system in continuous time,
we introduce an ensemble of random Lindblad operators, which generate Markovian
completely positive evolution in the space of density matrices. Spectral
properties of these operators, including the shape of the spectrum in the
complex plane, are evaluated by using methods of free probabilities and
explained with non-Hermitian random matrix models. We also demonstrate
universality of the spectral features. The notion of ensemble of random
generators of Markovian qauntum evolution constitutes a step towards
categorization of dissipative quantum chaos.
