Facebook seems to be testing a new feature that will allow you to find the nearest wireless hotspots (Wi-Fi).
Some time ago, Facebook started asking its pages to provide Wi-Fi to their customers in their physical addresses. 
It seems that information these could be used for the new social network project, although the results could be somewhat inaccurate, as no one can say for sure if the administrators of the pages did not lie about providing Wi-Fi.
The new feature first appeared in the iOS app but not globally. At the moment, it's not clear whether Android users have the feature. Those who were asked did not have it, but that does not mean that there are not some lucky Facebook users who have it.
As for iOS, as mentioned above, it has not been released for everyone yet.
If you are one of the lucky ones, you can locate the function in the hamburger menu available for the mobile app.
