http://uwb25d43nnzerbozmtviwn7unn7ku226tpsjyhy5n4st5cf3d4mtflqd.onion/posts/grapheneos/index.html
For this reason, we recommend that you leave your smartphone at home and use it like a landline, connecting to the Internet via Wi-Fi in airplane mode, rather than using a SIM card to connect through cell towers. Even if you use an anonymously purchased SIM card, if it is linked to your identity in the future, the service provider can be retroactively queried for all geolocation data.