The ability for an application to display content on top of other applications is a feature present in the Android operating system. This system functionality allows an app to create overlays, appearing above other running programs. A practical example of this is a floating chat head that remains visible regardless of the active application.
This capability provides numerous advantages, ranging from enhanced user accessibility to innovative application functionalities. Historically, it has been utilized to create tools that improve multitasking, accessibility services offering personalized assistance, and apps with custom interface elements that augment existing applications. It should be noted that the unrestrained or malicious implementation of this feature can result in security vulnerabilities and compromised user experience.