Top: part of the X-shooter counts spectrum of RBS 334 in the VIS arm after a median filtering with a 3-pixel window. The absorption features are identified as corresponding to the Ca I G (left) and CaI+FeI (right) lines for z = 0.411. The expected positions are indicated by the dashed vertical lines. Bottom: UV-to-NIR spectrum of RBS 334 (in black) along with the result of our modelling (in red) based on a fit of a galaxy template (in green) and a power law (see Sect. 3 for details and Table 8 for results). In the insets, zooms in regions where different absorption features were identified at z = 0.411 after flux calibration and telluric correction, which corresponds to Ca II H&K, Mg, CaI+FeI, Na I D, and the two stronger absorption lines of the calcium triplet.