[Mg/Mn] versus [Al/Fe] plot, color-coded for each detected group. A kernel density estimation (KDE) plot of MW disk stars is shown with gray curves. These were selected from APOGEE DR17 following the same quality criteria as our halo stars, and V_ϕ ≥ 100 km s⁻¹. Straight lines mark the boundaries of the accretion and in situ high- and low-α loci used in Das et al. (2020). The G2 (GSE) locus is mostly limited in this plot by [Al/Fe] < 0 and [Mg/Mn] > +0.2.