Comparison between the velocity width of the Mg II (x-axis) and the C IV (y-axis) systems found to be matched within ±150 km s⁻¹ along the line of sight We show the $\mathrm{\Delta }{v}_{90}^{\mathrm{Mg}\mathrm{I}\mathrm{I}}=\mathrm{\Delta }{v}_{90}^{\mathrm{C}\mathrm{I}\mathrm{V}}$ relation (gold line) with the shaded area marking the typical 1σ uncertainty on the kinematics. Open squares highlight the Mg II and C IV systems whose absorption line profiles are matched in velocity space. The inset shows the velocity shift between the peak of the Mg II optical depth relative to the C IV for the full sample (lightgray) and restricted to only the matched systems (black).