What is a savefile?
Savefiles are a very convenient, compact, and fast way to store game data. Almost all games need to make regular use of savefiles for storing player info, character data, world information, etc. You can save objects, mobs, or arbitrary data directly to a savefile. A savefile is not a true database, but a way to have a hierarchy of data inside a file. BYOND also provides full access for reading and writing your own files, so you can bypass savefiles if you wish. Most likely, though, you’ll find them to be what you want for storing data.