How to change the usb name of Atmel 32u4? I want to change my Arduino Leonardo's name that Windows shows me when it's plugged in.

I know that i have to change its firmware to change the name but I cant find firmware for it on the Internet.

On Arduino Mega, I have changed it with a downloaded firmware via flip, but I can't change the file because it's a .hex.
The Arduino '32U4 bootloader, Caterina, can be found under hardware/arduino/bootloaders/caterina. It requires LUFA in order to build.

With the technical part aside, note that you are not allowed to use the USB IDs assigned to Arduino LLC with products you intend to distribute under another name. You will need to acquire your own vendor ID from the USB-IF if you want to do so.