The FBI has been unable to access a Washington Post reporter’s seized iPhone because it was in Lockdown Mode, a sometimes overlooked feature that makes iPhones broadly more secure, according to recently filed court records.
The court record shows what devices and data the FBI was able to ultimately access, and which devices it could not, after raiding the home of the reporter, Hannah Natanson, in January as part of an investigation into leaks of classified information. It also provides rare insight into the apparent effectiveness of Lockdown Mode, or at least how effective it might be before the FBI may try other techniques to access the device.
“Because the iPhone was in Lockdown mode, CART could not extract that device,” the court record reads, referring to the FBI’s Computer Analysis Response Team, a unit focused on performing forensic analyses of seized devices. The document is written by the government, and is opposing the return of Natanson’s devices.
Archive: http://archive.today/gfTg9


Well yes of course, but you are still giving away your data, regardless of intention. And a privacy feature of GrapheneOS is that it redirects location data requests to the OS by default. Thats why you have to disable it in the settings if you want Google to have this data.
AFAIK it is specifically meant as a replacement for SMS and is used with regular pre-installed SMS Apps.
Nope
Only works with 3 proprietary apps, that I’m aware of. Google and Samsung Messages and iMessage.
https://en.wikipedia.org/wiki/Rich_Communication_Services
I have no deeper knowledge of this topic, but to me it seems like Wikipedia is disagreeing.