A new report, based on documents obtained through public records requests, sheds more light on the kiosks, which are backed by a subsidiary of Google’s parent company, Alphabet. The report, by tech news site Recode, provides further evidence about how the kiosks—which are skinny and about 10 feet high—are about much more than just free public Wi-Fi and device charging.

It turns out the kiosks also have the ability to measure pollution and sense gas leaks. They also can deploy cameras to monitor pedestrians and vehicles passing by.

According to promotional material from Sidewalk Labs, the outfit that makes the kiosks, the information from the cameras can help cities improve traffic flow, and even monitor for suspicious packages that could be tied to terrorism.

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So far LinkNYC, the company that operates the New York kiosks, has yet to turn on the cameras—no doubt out of concern that doing so will give rise to Big Brother-style privacy fears. (Update: a spokesperson for Sidewalk Labs said by email that privacy is not the issue, but rather the delay on deploying cameras is related to contractual negotiations).

If and when the kiosk cameras are ever turned on, they could yield a data bonanza for cities, and for Google, which would reportedly feed all that information back into its Maps service.

All of this is consistent with a vision set out by the CEO of Sidewalk Labs, Dan Doctoroff, at Fortune‘s Brainstorm E conference last month. At the time, Doctoroff claimed that the advent of sensors and smartphones represents a “fourth revolution” that would remake our cities (the prior revolutions were the steam engine, the electrical grid, and the automobile).

It will be curious to see how fast cities and their residents come to embrace the data potential of the Wi-Fi kiosks — or if fears of privacy will lead cities to keep those sensors turned off for the foreseeable future. In a statement, the COO of Sidewalk Labs, Anand Babu, described the promise of technology this way:

“We’re excited to collaborate with cities to design connected kiosks that meet their goals – providing free Wi-Fi, interactive city services and real-time transit information to travelers while ensuring privacy and security.”

Finally, here are some interesting financial tidbits from the Recode report:

• It will cost cities around $33,000 per kiosk for initial installation and fiber optic charges (though the kiosk itself is free).
• The annual cost for maintenance, power and so on is listed at around $13,000 per kiosk.
• Sidewalk Labs will offer to install screens and sell ads on the kiosks—which could raise $60,000 annually in ad revenue, half of which would go to the city.

It will be curious to see how many towns across the country decide to install the kiosks. While those here in New York have attracted lots of buzz (including a flap over homeless people using them to watch pornography), it’s unclear for now if they will fulfill their promise of becoming long-term fixtures of urban life.

(This story was updated at 3:45pm ET)