Official site: https://www.iceblock.app/
The CNN article talks a bit more about privacy issues. This bit caught my eye:
It’s only available on iOS because Aaron says the app would have to collect information that could ultimately put users at risk to provide the same experience on Android.
I would like to see some details about this. Perhaps there’s a way to work around that problem, even if it meant publishing on F-Droid instead of Google Play.
Sightings are tiny and compressible you could download all the sightings then diffs and never leak anything but ip or if a VPN not even that.