Graph Editors menu > Track View - Dope Sheet > Edit Keys
Main toolbar > Curve Editor (Open) > Modes > Dope Sheet > Edit Keys
Edit Keys displays your animation as a series of keys as boxes on a grid in the Key window. Dope Sheet Editor turns on Edit Keys by default.
Edit Keys is useful for getting a global view of your animation because it displays animation timing for all tracks. Use this mode for key and range editing when you want to view your changes in the context of the total animation.