Final answer:
An undocumented yet benign hidden feature activated by commands, keystrokes, or mouse clicks is known as an easter egg. Developers insert them for a playful surprise for users to find.
Step-by-step explanation:
The type of undocumented yet benign hidden feature that launches after a certain sequence of commands, key combinations, or mouse clicks is known as a d. easter egg. Easter eggs are secret responses that developers hide in software, games, and even in some operating systems. For instance, you may find that typing a special phrase or performing a specific sequence of mouse clicks activates an animation, game, or message that isn't typically part of the program's core functionality. These are intended to be fun surprises or bonuses for users to discover.