The stochastic gravitational-wave background is a superposition of many astrophysical and cosmological sources, such as unresolved compact binaries, cosmic strings, and phase transitions in the early Universe. We highlight the importance of source separation in the case of a detection. By separating the individual sources, we can reveal remnants of early-universe processes. We use the data from the third LVK observing run to explore the parameter space of first-order phase transition models. We then investigate signs of parity violation in gravitational-wave data.