[Seeker]

The unknown white box is a 4 pin Suzuki plug with a cover on it presumably for an option of some kind. The cover itself has two pins inside which (I'm guessing) are shorted together to make a connection to something in the loom when the cover is fitted. My bike has the same (I had a quick look).
You have 2 ancillaries connected - you pointed out the Garmin on the left but the (indicated) fuse on the right is another "extra" - do you have a connection for a battery tender or perhaps heated grips?

It looks like the big red loop at the top of the picture is the source of the power although I cannot see where it is tapped into from the angle of the picture. The loop feeds power into the "triangle of death" (thought I'd add some drama) which feeds your Garmin on the left and the mysterious flux capacitor's fuse on the right.