What is Adobe Flash Builder use for?

Adobe Flash Builder is an integrated development environment (IDE) used for building applications using the Adobe Flash platform. It allows developers to create rich internet applications (RIAs) and mobile applications using ActionScript and MXML. The tool provides features like code editing, debugging, and performance profiling, making it easier to develop, test, and deploy applications across different platforms. However, it's important to note that support for Flash has largely been discontinued, and modern web development has shifted towards other technologies.