How are you getting 7.3V on a 5V square wave?
And what's your vertical scale?
Well, part of it is just the overshoot/ringing on the transition. Here's zoomed in and I've highlighted what I think is kind of strange. The measurements say max voltage in the waveform is at 5.6V, but the waveform is above the trigger level which claims to be set to 6.4V. Maybe I haven't gotten the hang of what the measurements mean -- there are so many crazy ones to choose from.
This is 5V/div and the waveform looks to go to about 7V on the graticule. I wouldn't swear to how well 0V is lined up to the division below though. The ringing/overshoot goes down about the same amount too. Which I took to be what Vpp is measuring, but if the measurements are just based on what appears on the screen, then 7.8V makes sense vs. what appears against the graticule and who knows what the Max is getting at.
Anyhow, I am very new to this scope and although I have seen all the videos, I still am having trouble groking the features.