WhatsApp is just one of them. There are plenty more , I have them on my tongue.
Trying to change the icon for it.
There are two applications folders in the iOS file system. The one you're looking for can be found in iFile by hitting the home icon in the bottom bar and then going into Applocations (folder path here is /var/mobile/applications). It contains the apps downloaded from the AppStore.
The second applications folder is at /var/stash/applications. That one contains native applications.