We require a few permissions to gather the data we show you. On devices running Marshmallow or higher, you don't need to grant any permission on installation, but we'll ask you when we need it and you can decide if you want to grant it or not. All permissions are optional, but some values will be left blank if we can't access the data. Here's a list of the permissions that Android considers dangerous:
Draw over other apps
This is requested when you use the overlay to show you power and CPU usage in real time on top of other apps.
Access app usage stats
We need this to gather the data to calculate per-app power usage. This is an optional feature, it not granted, some parts of the discharging screen will be empty.
Access external storage
We use this for data export, but in the current version of AccuBattery, this feature isn't available yet and this permission is never requested.
We don't require any other sensitive permissions like contacts, email, calendar or location as we have no use for that.
On devices running Lollipop, "access external storage" and "draw over other apps" is granted on installation, but "access app usage stats" still has to enabled by you manually, and you may chose not to if you prefer that.