The epilogue or follow-up to a story that proves the "outcome" of the story is real or imagined, good or bad
Technically speaking, the moment of climax in a story is the intersecting point where the nature of the Main Character crosses paths with the nature of the Overall (Objective) story. It is here that the course of one, both or neither of them may be altered by the interaction. The only way an audience can be sure what, if anything, has changed course is to plot one more dramatic point past the climax, as part of Act 4 to illustrate the new direction of the Overall (Objective) story and Main Character. This might be the "?" after the words "The End" in a monster story or a formerly mean man sharing his sandwich with a stray dog on the way home. The purpose is simply to illustrate that the suspected effect of the climax has or has not truly resulted in a change in course. As such, it functions as the Author's Proof and is a key component of the denouement.