MagE optical spectrum of Sapaki in the range 3800−7200 Å at a resolution of R = 4100, shown at the top. The remaining panels display comparisons between the spectra of Sapaki (black), HD 93129A (O2If*; blue), Cyg OB2-22A (O3If*; red), and Cyg OB2-7 (O3If*; green), in the wavelength ranges of 4010−4190, 4310−4490, 4590−4740, 4760−4940, 5750−5950, and 6470−6690 Å, at a common resolution of R = 2500. Cyg OB2-7 lacks data for the bluest and reddest regions, whereas Cyg OB2-22A lacks data in the reddest regions. The lines marked with colors are Hη, Hζ, Ca II H, Hϵ + Ca II K, He IIλ4026, N IVλ4058, Si IVλλ4089-116, Hδ, He IIλ4200, Hγ, He Iλ4388, He Iλ4471, He IIλ4542, N V λλ4604-20, N IIIλλ4634-40, C IVλ4658, He IIλ4686, He Iλ4713, Hβ, N IIIλ4905, N Vλλ4933-44, He IIλ5411, C IVλλ5801-12, He I λ5876, Hα, He Iλ6678, C IIIλλ6721-27, C IIIλ7037, and N IVλ7116. The DIBs marked are λ4179, λ4429, λ4727, λλ4762-80, λλ4881-87, λλ5780-97, λλ5843-45-50, λλ6492-94-98, λ6527, λ6613, and λ6660.