  Numerical simulations of expanding plasma based on the AdS/CFT correspondence
as well as kinetic theory and hydrodynamic models strongly suggest that some
observables exhibit universal behaviour even when the system is not close to
local equilibrium. This leading behaviour is expected to be corrected by
transient, exponentially decaying contributions which carry information about
the initial state. Focusing on late times, when the system is already in the
hydrodynamic regime, we analyse numerical solutions describing expanding plasma
of strongly coupled N=4 supersymmetric Yang-Mills theory and identify these
transient effects, matching them in a quantitative way to leading trans-series
corrections corresponding to least-damped quasinormal modes of AdS black
branes. In the process we offer additional evidence supporting the recent
identification of the Borel sum of the hydrodynamic gradient expansion with the
far-from-equilibrium attractor in this system.
