Latest Arduino sketch can be found in "RfArduinoCodeBase" directory. It's dependent on rc switch arduino library. There's a step by step guide Hack-Remote-RF-Security-Locks-With-Arduino-and-Usb ...

Arduino lib to clone and replicate 433/315Mhz devices that are not using standard protocols. - SorSayyadi/RC-Switch-easily-clone-any-remote ...

The Arduino rc-switch library proved unable to decode the signal, but some Python work helped him get to the bottom of it.