Greek NT INT+ is based on the ν = ΝΑ28 [=UBS5] text.
By textual variants for example spelling variants of "David" is the dark grey based on other sources.
α = Alexandrian [= UBS3/UBS4/NA26/NA27]
τ = Stephens 1550 Textus Receptus
σ = Scrivener 1894 Textus Receptus
β = Byzantine Majority
So ν = ΝΑ28 [=UBS5] text is never dark grey.