Shift of centroid of C IVλ1549 Å line in units of km/s, as function of logarithmic luminosity νL_ν at 2500 Å, available in Wu & Shen (2022). The sample consists of all the quasars in the SDSS DR16 sample with redshift in the z = 1.8–2.2 interval, colour-coded from red to black by the density of the underlying points. Empty cyan circles indicate 45 objects pre-selected for the one-by-one modelling of the C IV line with multiple components. Filled semi-transparent blue circles show a subset of 10 objects with the confirmed strongly blueshifted component, the main dataset analysed in this paper. Violet circles show four supplementary archival sources.