The carriers have access to everything. Phone calls, text messages, search histories, usage histories, locations, elevations, movements over time. As modern people we have mostly chosen to pretend like we aren't aware of how vulnerable we are. But what information have these law enforcement agencies been after?
The companies basically did not say anything about who is requesting what. It could be anything from a 911 operator needing to know the location of an incapacitated caller (scariness quotient: very low) to the FBI wanting to know the call history of a suspected terrorist (scariness quotient: pretty high) to a blanket request from a local police force seeking unwarranted wiretaps (scariness quotient: extremely high). Many of those calls, including the three I just named, can be called "emergency" requests which require no warrant or waiting period.
How many were emergencies? No idea.
Then there were "tower dumps," in which a law enforcement agency makes one request to access all the information from one entire tower. This could allow them access to hundreds or thousands of users. A tower dump, by the way, counts as one of those 1.3 million, even though it affects many, many more.
How many were tower dumps? We wonder.