On June 8th, 2021, Amazon will automatically activate a feature called Sidewalk. This is a way to extend networks beyond your own home to your neighbors, or to your sidewalk. Because of bandwidth limits, neighbors will not be able to use your WiFi signal for watching Netflix or web surfing, but this whole idea makes me uncomfortable.
Amazon says it will possibly enable your devices to continue working to a limited degree if you have a power failure but your neighbors don't. For example, your Ring Doorbell may continue to function, except for uploading its videos, using your neighbor's network while your power is out. Sidewalk may also help you add devices to your network more easily, though I haven't seen an example of how this can work.
I think the bottom line is anyone passing by your home with a Sidewalk enabled device can connect to your Sidewalk network. That ain't gonna happen at my house, because I've disabled the feature. Here's how to disable it on your Amazon devices.
Open the Alexa app.
Tap More in the bottom, right corner.
Tap Settings on the left.
Tap Account Settings on the left.
Tap Amazon Sidewalk.
Tap the blue bubble on the right to disable. If the bubble has a gray dot, then Sidewalk is already disabled.
Read this PC Magazine article for more information: