Board Thread:General Discussion/@comment-26006155-20200107155350/@comment-32182236-20200203145246

Even AAA games have unused files. It's actually surprisingly common for plenty of unused files to exist. Some games even have fully functional unused levels!

There's often a very good reason to keep unused files in:https://www.reddit.com/r/explainlikeimfive/comments/64vtp9/eli5_why_do_video_games_have_leftover_or_unused/

https://www.reddit.com/r/gaming/comments/930em9/why_are_unused_files_maps_assets_even_larger/

Here's an example:There exists an unused "mushroom" character in the original Super Mario Galaxy, by the name of "Kinoko". https://tcrf.net/Super_Mario_Galaxy/Unused_Models

However, if that file does not exist within the game, the game crashes. The same is the case for the second game.

This is likely because back when the mushroom was the playable character (For testing purposes, surely), the rest of the game was built relying on THAT. So, even after the mushroom became unused, it was still being called for, and removing it crashed the game.