Spectra of the diffuse nebulae in the DB10 (left) and DB11 (right) regions. The positions of the Brγ and the He i 2.113 lines are marked by vertical dotted lines. The lower panels are a zoomed-in version in the wavelength region of the He i 2.113 line. The horizontal dashed lines represent 1 and 3σ levels above the continuum. The squares and the circles represent the expected peak values of the He i 2.113 line in the case of a 1% and 3% He i/Brγ flux ratio, respectively.