The 02 for the first octet just sets the «locally assigned» bit, which makes it obvious that it's not a vendor-provided MAC address, and guarantees that you won't collide with a real NIC's MAC address.
Usage: macchanger [options] device
-h, --help Print this help
-V, --version Print version and exit
-s, --show Print the MAC address and exit
-e, --endding Don't change the vendor bytes
-a, --another Set random vendor MAC of the same kind
-A Set random vendor MAC of any kind
-r, --random Set fully random MAC
-l, --list[=keyword] Print known vendors
-m, --mac=XX:XX:XX:XX:XX:XX Set the MAC XX:XX:XX:XX:XX:XX