The real star of that show is the very nicely controlled dispersion that matches the on-axis response. That is very good control of directivity.
One interesting thing to note is that there is an on-axis null at 20kHz but an off-axis flare of energy in that same range. Dogs and bats probably find this speaker obnoxious! I would guess the reason for that maybe a breakup mode throws the tweeter in reverse phase that, combined with the horn geometry, creates a phase cancellation null on axis but creates a big spike off axis. It's not a big deal though, since few adult humans can hear that high. Young children can, however.