Did you tell windows that it could use your kindle "usb drive" to accelerate windows? If a USB mass storage is fast enough, windows will ask this sometimes when it detects the device.
If you said yes, you gave windows permission to store "crap" on your kindle.
If you did not say yes, then you may have "malware" on your windows PC. Because that filename looks like part of a URL (web page address), I suspect it may be caused by malware, or some other badly behaving program that you installed.