Not all of the developers' ideas made it into the release version of the game.
The mod community continues to explore the early version of Fallout: New Vegas. During development, Obsidian Entertainment discarded some ideas and now they are trying to restore them.
Enthusiasts have gained access to post-ending content:
They learned that the authors of Fallout: New Vegas planned to introduce additional dialogues that were tied to the ending chosen by the player.
For example, in the case of the NCR's victory, companion Cass will be happy that the hero got rid of the Legion, and will also state that she will name her child in his honor.
If you hand over power to Mr. House, he will thank you for your cooperation and allow the protagonist to keep an apartment in the "Lucky 38" as a bonus.