To understand the necessity of a flashable ZIP, one must first understand the legal architecture of Android. The Android Open Source Project (AOSP) provides the core operating system code, which is free for anyone to use and modify. This is what powers custom ROMs like CyanogenMod (now LineageOS) or AOKP. However, Google’s proprietary applications—such as the Play Store, YouTube, and Google Search—are closed-source. Due to licensing restrictions, custom ROM developers cannot legally bundle these apps directly into their ROM downloads.
: Google officially ended Google Play Services support for Jelly Bean in August 2021. While you can still install the apps, many modern apps on the Play Store will not be compatible. Project Butter official gapps for android 411 jellybean flashablezip