Corner plot derived from the MCMC fitting of the C IV and He II (see Sect. 4.2). In this figure we show the correlation between the free parameters in the C IV+He II fit. The λ_He II and λ_C IV,2 are the line centers of the He II and blueshifted C IV (for the 1548 Å line) emissions in Å, respectively. The F_He II, F_C IV,1, and F_C IV,2 are the integrated line fluxes of He II, systemic C IV, and blueshifted C IV (only for the 1548 Å line) emissions in 10⁻²⁰ erg s⁻¹ cm⁻² Å⁻¹, respectively. The FWHM_He II, FWHM_C IV, and σ_C IV,2 are the line widths of He II, systemic C IV, and blueshifted C IV (for the 1548 Å line) emissions in Å. z_i, b_i, and N_C IVi, which are the fitted redshifts, Doppler parameters (in units of km s⁻¹), and column densities (logarithmic) of the four absorbers. The black dotted lines in each of the histograms represent 15.8 and 84.2 percentiles, which correspond to the reported uncertainty ranges. The blue solid lines mark the median and reported fit values, respectively.