Star

From APIDesign

APIs are said to be like stars. Star cannot know "who's watching" and cannot "just disappear". It may explode, turn into supernova, burn out. However there are physical laws that prevent it to "disappear suddenly" (unless god would play dice with us).

Just like that a method in an API cannot be "just refactored away". There are laws of API Design that require it to behave properly (if one wants to be real API designer and not play dice with users of the API).

More in the Diamonds vs. Stars allegory.