JWST/NIRSpec mock spectra illustrating how the mass-loss rate affects the detectability of a spectral line, in particular C IVλ1550 Å. The figures depict the spectra for a star with T_eff = 30 000 K and a redshift of z = 6. The left figure compares different mass-loss rates and illustrates its effect on the strength of the emission part of the line, while the right figure shows how the spectral line is consistently detectable up to 28 AB mag if a high mass-loss rate is used.