The Tesla Model 3 has eight cameras on the outside of it to help enable its driver aids and security features, but there’s also one inside that doesn’t do anything…yet.

But it may help you earn money one day, if Telsa’s plans for an autonomous ride-hailing network come to fruition.

CEO Elon Musk has previously detailed the long-term goal for such a system, which would theoretically allow owners of fully self-driving Teslas to hire them out as taxis when they’re not using them for themselves.

Responding to a Twitter question about it from one of his followers, Musk revealed that the camera above the rearview mirror is primarily there to keep an eye on passengers using the service and provide evidence if anyone “messes up” a car.

He added that the cameras can also see out of the windows to provide additional input for other features.

While some have speculated that it could also be used as a monitor to help assure that a driver is watching the road while using the semi-autonomous Autopilot system, Musk did not suggest that possibility, instead pointing out that owners will have the option of turning it off completely.

A recent CNBC report detailed how much unencrypted personal data, including video, is stored onboard a Tesla and able to be extracted after an accident if not intentionally wiped clean by the owner.

The interior camera is not present on the current versions of the Model S or Model X.

Musk said that more information about the ride-hailing scheme and the technology behind it will be released during a webcast on April 22.

WHAT ARE THOSE HOLES IN MY DASHBOARD FOR, ANYWAY?