I suspect it is what is euphemistically called fill-flash, easily obtained by keeping the flash on in daylight to remove shadow. It was something I learned from a magazine article and tends to work well on portraits.
Flash fill is what used to be called daylight flash in the days of film. A fast speed and dialled down flash output, down as low as -1 or even -1.5 can reduce silhouette by a significant amount. But then again, it's only what I'm alleging (allegedly)!
That last one is a work of art.