A tracker is a piece of software, often as part of an app, that is implemented to collect data about a user and their behavior and send that data back to the app developer and third parties, if third party integrations are built in (which is often the case). The tracker can extract personal data (your credentials or payment details), behavioral data (how often and when you use the app, which parts you interact with the most) and meta data (your location, your device type, your language, your screen size etc). Many apps include software by Google or Facebook, because that makes part of the development process faster and easier for the developer, but to the disadvantage of the end user, whose data is then being collected by these Big Tech companies. These are advertising companies who use and sell your data for profit.
