ALICE measurements of groomed $\lambda_{\alpha,\mathrm{g}}$ for $\alpha=1$ (`girth,' left), $\alpha=2$ (`thrust,' center), and $\alpha=3$ (right) using $R=0.2$ charged-particle jets with $40 < p_\mathrm{T}^\mathrm{ch\; jet} < 60$ GeV/$c$ in pp and Pb--Pb collisions at $\snn = 5.02$ TeV compared to models. The bottom panel shows the ratio of Pb–Pb distributions to pp, which quantifies the substructure modifications from quenching. These ratios are visibly enhanced as compared to the ungroomed distributions shown in Fig. 2, signifying a strongly quenched jet core.