MoonshineMidnight In almost every modern country, the Police can simply ask for your CURRENT position, as well as your historical position months or years in the past.
Police would mostly use warrants.
If you are not committing crimes, you have very little to worry about in a European country.
It seems that this part is continually overlooked.
If you loaded GrapheneOS, never installed an app, never answered a text or call, and merely carried it on your person, IF YOU ARE TARGETED BY A CRIMINAL OR INTELLIGENCE INVESTIGATION (that's the important part!) they can and will put together who you are running with.
"Oh but I go dark" (airplane mode, faraday bag)
Very likely, so did your compatriots. That actually identifies you.
"I use a burner"
Have you ever had them on at the same time? Same general location? Gotcha.
Start with one person, follow their patterns of movement, and then see who they are repeatedly near (excluding family, etc).
Boom.
It's pattern analysis.
It only requires the phone company. Not Cellibrite, NSO, or NSA TAO.
This is what you have you think about. Stop looking for the deep technological thriller plots and look at the simplest angles.
A (suspected) criminal was tailed physically or electronically. Some of their associates were identified. The cellular system and some cheap software does the rest.
If they "broke" Signal, you would likely never hear about it since it's too valuable of an exploit to waste on some simple criminals.
They simply use "parallel construction" and find another "reason" they identified you.
If they can pretend they've broken Signal, they can throw you off the scent.