Answer:
The answer to this question is given below in the explanation section.
Step-by-step explanation:
The extension apex stands for the Android Pony Express Package file.
It is a zipped compressed package file that Google and other Android device manufacturers use for distributing updates to low-level system libraries on Android devices. It contains security updates deployed to Android devices. For example, instead of waiting to publish a full system upgrade, a device manufacturer can update an individual library to apply a patch or add a system feature.