YML - YAML Document is good for creating different files that are in the YAML format. It is mainly used for readable data formats as well. You will successfully be able to get different data to be used and read separate from other languages. You can also take advantage of other file types when using this extension. You can also connect right to a database if you want to use this extension. It really comes in handy when you need it the most. There are also many different programming languages that can be used right along with this file extension. You just need to make sure that they are supported and compatible. You will also be able to download this extension online.