You can see the shutter moving at 19:20-19:40 in the video, when Dave was waving at himself - look at the sensor when the screen freezes.
!!
So that settles that. But, I'm still as puzzled as Dave as to
why they would put a shutter on it, though. They don't need it for the application.
Likely, the intended method to access those screws is to actually remove the front glass panel, possibly using heat. This is common for example in certain smartphones. Or, it may just have been designed to basically be indestructible, and otherwise disposable.
The 8 MHz is likely not used directly as the CPU clock. The datasheet for STM32F103 specifies that it has a PLL which takes a 4 to 16 MHz input, so you would never clock it directly at the CPU frequency anyway. As for the bizarro device, you guessed it, the traces are snaking off to the 32 kHz oscillator pins, according to the same datasheet.