Wiring ripped off from chain

I took a picture of this little doo dad that got ripped off my bike when it was running. I have no idea what it is or what it does. Any idea of what it could be? My roommate's uncle said it was a capacitor for my starter and said it could/would lead to more problems (my bike would have to run first!)

78 kz650b

I believe it's the brake light failure indicator switch. It's near the lower right corner in the wiring diagram (see link); compare the wire colors. Ed

diagrams.kz650.info/wiring/images/KZ650-B2,C2.jpg

kzrider.com/forum/4-electrical/585794-name-this-part

same thing i asked about the other day