Blind absorption line scan performed on the joint XMM–Newton (0.3–10 keV) and NuSTAR (3–25 keV) spectrum. At each trial energy, a Gaussian absorption component with fixed width of 0.04 keV was added to the continuum model, and the improvement in fit statistic (Δχ²) was recorded. A prominent and narrow peak is recovered at ∼3.3 keV, corresponding to the candidate cyclotron feature.