In 2003, distributions started to include metadata files, called META.yml, indicating the distribution's name, version, dependencies, and other useful information; however, not all distributions contain metadata. When metadata is not present in a distribution, the PAUSE's software will try to analyze the code in the distribution to look for the same information; this is not necessarily very reliable. In 2010, version 2 of this specification was created[9] to be used via a new file called META.json, with the YAML format file often also included for backward compatibility.