Everything on the 1.44mb disk is data, and data can be visualized! (In fact, if you want to really dive deep into data visualization on Sector Disk, check out this tutorial on creating visual sectors from .png files!)

Here, all of the data is visualized as blocks, where each 16x32 pixel block represents a single sector:

Here, it is visualized in a more linear fashion, where every pixel (left to right) represents one byte of the disk from beginning to end.

These images are refreshed every day at 6:29AM UTC (they might take a bit of time to generate, depending on how much disk activity there is at that time. The program does have to read the entire disk, after all). You can see an archive of these images here.