WhatsApp is a popular messaging application that allows users to send and receive messages, make voice and video calls, and share media files. WhatsApp can be accessed through its mobile application or through WhatsApp Web, which is a browser-based PC client of WhatsApp messenger.

There is no app called "wab" that is related to WhatsApp. However, there are third-party apps available on the App Store, such as "Web Messenger for WhatsApp Web," that allow users to access the web version of WhatsApp on their mobile devices.

It is important to note that third-party apps may have different privacy practices than the official WhatsApp application. Users should be cautious when using third-party apps and ensure that they are downloading from a reputable source.