Hoverzones are regions defined by a color and a list of coordinates that form a polygon. They are only active when the scene is un-zoomed. Be sure to move your pointer over the east and west coasts and observe the "hotzones" that pop-up when you are over the pre-defined (in the file_of_filenames) regions.

Then enable the "Watches" overlay, and move your pointer over each of the colored watch areas. This overlay is associated with some hotzones that are defined in the "fof extension" file named watches.txt, using the hotzone= parameter, which links the color of the area in the overlay along with the overlay number. There is a "tooltip" that defines the watch number, and if you click on the associated hotzone, you will get a pop-up window containing the text of the associated watch, which is also specified in the hotzone parameter.

The other two overlays are just simple image files...

Finally, the SSEC logo is a hotspot defined with an icon, similar to FlAniS. Like the others, it is also clickable...