The term refers to a code which is implemented to an app. The purpose of it is to target the usage of an app and record its parameters. In other words, the code allows for developers to track how often their app is being used, the stability and the main functions of the app.
The code is a must know for all app developers. It monitors and records the most commonly used segments of an app and allows for developers to adjust the app, add new features and remove the irrelevant ones. It is also essential for making the apps smarter and easier to use.
If you understand the code and how it works, it will allow for you to use the apps or modify them accordingly, so the ads are displayed at the perfect time, in a perfect location. Basically, you will be able to adapt an app for higher conversions and more sales.