Integration with PMX
WhatsRunning is integrated with PMX so you can open one from the other.

So from WhatsRunning you can switch to PMX to find out what permissions a running (or dead) app is granted.
Similarly, from PMX you can switch to WhatsRunning to find out if an app with restricted permissions is still running. If yes, in what state it is and how much resources it is using.
This is particularly helpful when analyzing the effect of permissions like RUN_IN_BACKGROUND.