Effectiveness of the f415²⁵ photometric filter. Panel a)m_f415²⁵ vs. m_f415²⁵ − I CMD. Canonical and anomalous stars, selected by means of the BVI index, are colored azure and red respectively. The azure and red fiducial lines mark the RGB boundaries, defined as the 4^th and 96^th percentile of the pseudo-color distribution. Average color and magnitude uncertainties are shown with the gray errorbars on the right of the CMD. Stars in common with Tautvaišienė et al. (2022) are marked with empty large circles. Panel b) Verticalized CMD of panel a). Panels c1-c3) Verticalized color distribution of stars in the three different magnitude ranges highlighted in panel b. The orange lines represent the Gaussian KDE.