F-Droid is an installable catalogue of FOSS (Free and Open Source Software) applications for the Android platform. The client makes it easy to browse, install, and keep track of updates on your device.
This is a bit of a fallacious point in this context - it suggests:
apps will be investigated by its users (not guaranteed, nor even likely for unpopular apps)
an app will even have users capable of detecting malware (I don't know squat about phone malware patterns, so I wouldn't be effective at it even if I did scan through thousands of lines of code)
The benefit of open source apps is anyone can view the code to see if there is malware or other installed.
This is a bit of a fallacious point in this context - it suggests: