When it comes to app development, not many of us realize just how much work goes into writing an app that's used by as many people as something like WhatsApp is. WhatsApp has become the de facto messaging application for a lot of people, and as it's a cross-platform application, not only will WhatsApp have a larger development team than most companies out there, but also a lot more work to do given the specific requirements for each platform. In a world where Apple controls their own App Store, one which has strict requirements that developers need to follow, it's perhaps not all that surprising that there is a little bit of "up yours" found within some code in the WhatsApp app.
Redditor u/xMarioZ was decompiling the Android APK - of version 2.16.254 for those looking to try this themselves - and throughout the code found a number of - not used - lines of code with "FUCK APPLE" in them. It's unclear why this has been left inside of the Android APK for WhatsApp, but as some Redditors have pointed out, there is cross-platform code that WhatsApp uses, and this cheeky reference is possibly present in both the iOS app as well as the Android app. Although, given Apple's stringent and arguably over-the-top approach to censoring things, it's unlikely these comments have survived into the iOS app.
Some of you might be wondering why developers would leave such comments inside of an app, especially when the iOS side of things probably makes up a huge portion of WhatsApp users. Well, the developers reading this probably will understand why, as the App Store often demands that code be written differently or behave in a different way purely to satisfy their own standards, as opposed to any sort of particular performance reason, and this often creates extra work as well as more headaches and hair pulling. It's this sort of reworking of code that puts back big updates of apps on Android, as developers want to make sure both major platforms get the update at the same time. Whether or not this code was left in by accident or on purpose is unclear, but it's one hell of an Easter Egg regardless.