Yes it treat different frequencies differently and inversely (for the low frequencies), that means the dB boost decreases as frequency increases. The dB boost also varies with output level, the lower you set the volume, the higher the boost.
I don't know where the DEQ effects will fall to zero, but based on my REW plots, it appeared to be around the 600 Hz mark. It boosts the very high frequencies too, appeared to start at around 9KHz. From that point on, the boost increases as frequency increases.
If we want to know for sure, we will have to ask Dr. Chris Kyriakakis, via Facebook or Twitter. IIRC he did respond to Pogre's question about the editor app once.
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