APK files are an archive file in `ZIP` format based on the JAR file format. The APK file usually contains the following directories:

* `META-INF` directory:
    * `MANIFEST.MF`: the manifest file
    * `CERT.RSA` or `CERT.DSA`: the certificate of the application
    * `CERT.SF`: list of resources and `SHA-1` digest
* `lib`: directory containing compiled code. The directory is split into more directories for each processor
  architecture (`x86`, `x86_64`, `armeabi`, `arm64-v8a` ...)
* `res`: directory containing not compiled resources
* `assets`: directory containing application assets
* `AndroidManifest.xml`: binary XML file describing the application (permissions, version, libraries ...)
* `classes.dex`: file in the `DEX` file format containing compiled Java code
* `resources.arsc`: file containing precompiled resources