You would be surprised how much technical data is available in some speaker tests. Impedance variations are always fun . This applies more to full range speakers than to subs.
People like Don Keele, who designed speakers for JBL and was the speaker/subwoofer tester for Audio magazine had the knowledge base, equipment, and experience to present more data than you would really want. To the point where you need the summaries to understand what all the test data and measurements mean.
Frequency response graphs are relatively simple in comparison, but unequalized room response curves typically look awful compared to anechoic chamber FR, which is often quite flat.