How it works: The system verifies the contents of the META-INF folder, specifically the MANIFEST.MF, CERT.SF, and CERT.RSA files, to confirm the app hasn't been tampered with.
Critical Note: Android does not natively run .jar (Java Archive) files as apps. If you see a website offering "Facebook.jar," it is likely a fake or a Java ME emulator file for very old phones (non-Android). For Android 4.4.2, you need a .apk file.
Downloading and installing the Facebook APK can have both advantages and disadvantages. On the one hand, users can access features not available in their region or install an older version of the app that they prefer. On the other hand, users may miss out on newer features and security updates, and there's a risk of installing malicious software if they don't download from trusted sources.