Windows 10 Spring Creators Update being a new Screen Capture API which developers can use to record frames from a display or application window, to create video streams or snapshots to build collaborative and interactive experiences.
The API invokes a secure system UI for end users to pick the display or application window to be captured, and a yellow notification border is drawn by the system around the actively captured item. In the case of multiple simultaneous capture sessions, a yellow border is drawn around each item being captured. The end user has to give explicit permission for the screen to be captured.
Developers can read more about the new API here.