File processors must be specifically written for each type of file format. Having said that, there are many files of differing types that can use the same file processor.
Text files are the classic case.
If you have a file type that you know is suitable for a specific file processor you can easily configure MantaDB to handle it. If you wish, you can write your own file processors that will index proprietary document formats. In practice not too many people will have the skills or the time to do this but there is always a small group who do. Only suitable for mp3 files. A HowTo Document discussing the addition of the mp3 processor dll is available.