  We pave the way for future gravitational-wave detection experiments, such as
the Big Bang Observer and DECIGO, to constrain dark sectors made of SU(N)
Yang-Mills confined theories. We go beyond the state-of-the-art by combining
first principle lattice results and effective field theory approaches to infer
essential information about the non-perturbative dark deconfinement phase
transition driving the generation of gravitational-waves in the early universe,
such as the order, duration and energy budget of the phase transition which are
essential in establishing the strength of the resulting gravitational-wave
signal.
