Comparison of the distribution of unresolved sources from Rubin DP1 in the r − i vs. g − r color–color diagram (symbols) and stellar model color sequences from Palaversa et al. (2025), which are in excellent agreement with SDSS observations. The sequences are color-coded by metallicity (−2.5 < [Fe/H] < +0.5, linearly from blue to red), but in this color projection they are primarily degenerate (for more details see Fig. 3 in Palaversa et al. 2025). Note: M stars with r − i > 0.5 have a mean g − r color of ~1.3, while in the SDSS photometric system, this is g − r ~ 1.4.