It's also available in Spanish, which is good. And from the site's description, it seems like it's helpful not just for organizers -- see the excerpt below.

I don't see why it would require a specific browser, as mentioned above, as long as you give the "app" permission to access your device's location. (I use another browser-based app that works like this, and it hasn't been a problem. But try it for yourself.)

https://antifreeze.app/

AntiFreeze lets anyone anonymously report an ICE sighting. When someone submits a report, every user within five miles gets a push notification on their phone in real time. If ICE is spotted four blocks from your house while you're making dinner, your phone buzzes and tells you.

But it's not just alerts... Open the app and you can see a map or list of every reported sighting within 25 miles from the last 72 hours. So even if you missed a notification, you can check what's been happening in your area before you head to work, drop your kids off at school, or go to the grocery store.

No login. No account. No personal data collected. Completely anonymous.

I would assume that its use would show up along with other websites visited, even if the "app" is deleted. But at that point, an average DU member is screwed anyway.

I'm using quotes around "app" because afaik it's not something that needs to be separately installed, but rather like a URL "shortcut" that you can save to your phone's homepage. That also would make it easy to delete in a hurry, without the chaos that deleting a browser would cause. (Android user here.) For those who are familiar, Sniffies uses the same system - it was also a workaround to avoid control by the Big [tech] Brothers.

If I'm mistaken about any of this, I welcome correction.