Sticky activation (or "sticky user activation") is a window state that indicates a user has pressed a button, moved a mouse, used a menu, or performed some other user interaction.
A page is considered "user activated" if a user is currently interacting with the page or has completed a touch, pointer, or keyboard interaction since page load. With sticky user activation, if activation is set it is not reset for the duration of the session (unlike Transient activation).
See Features gated by user activation for examples of APIs that require sticky activation.
UserActivation.hasBeenActive property to programmatically access the current window's sticky activation state.