I'm assuming there is some sort of stacking process involved in the software as well, but that's just how it came out. It actually provided me with a one second video of the process too where you can watch the Stars move a little. But the picture I posted is exactly as I got it off the camera, I posted it from the same phone I took it with.

Edit: here's the video, I converted it to a gif in the original orientation.

Yes, iirc it's 4 min worth of ~15 second exposures that get stitched together. Most smartphones within the last 5 years should be able to do this too. I know on my Pixel 7 you just have to put the camera in night mode and leave it still for a few seconds to trigger the astrophoto mode.

It probably crops in to overlay all images perfectly. I'm guessing if the trees were lit they'd be blurry.