Pen-testing is short for penetration testing. Which is testing if you can break into the things. Like a locked office or a computer system, etc. Legally, it's done to find flaws that need to be fixed before they get used nefariously.
Pen testing techniques and tools are essentially break in tools. In this case, a tool for mimicking car key fobs and the wireless signals they send to the car.
We're all trying to find the guy who did this!