Well, everything is there for a good reason. (Though it escapes me right now why it needs permission to access the calendar.) How are you going to call someone

Well, everything is there for a good reason. (Though it escapes me right now why it needs permission to access the calendar.) How are you going to call someone over Signal if Signal can't use the microphone? If in doubt you can always check the source code – it's open source for exactly that reason.