  Despite several decades of multi-wavelength and multi-messenger spectral
observations, Gamma-Ray Bursts (GRBs) remain one of the big mysteries of modern
astrophysics. Polarization measurements are essential to gain a more clear and
complete picture of the emission processes at work in these extremely powerful
transient events. In this regard, a first generation of dedicated gamma-ray
polarimeters, POLAR and GAP, were launched into space in the last decade. After
6 months of operation, the POLAR mission detected 55 GRBs, among which 14 have
been analyzed in detail, reporting a low polarization degree and a hint of a
temporal evolution of the polarization angle. Starting early 2024 and based on
the legacy of the POLAR results, the POLAR-2 instrument will aim to provide a
catalog of high quality measurements of the energy and temporal evolution of
the GRB polarization thanks to its large and efficient polarimeter. Several
spectrometer modules will additionally allow to perform joint spectral and
polarization analyzes. The mission is foreseen to make high precision
polarization measurements of about 50 GRBs every year on board of the China
Space Station (CSS). The technical design of the polarimeter modules will be
discussed in detail, as well as the expected scientific performances based on
the first results of the developed prototype modules.
