There should be an OSI approved license included in the repository. Common licenses such as those listed on http://choosealicense.com are preferred. Note there should be an actual license file present in the repository not just a reference to the license.
Acceptable: A plain-text LICENSE file with the contents of an OSI approved license
Not acceptable: A phrase such as 'MIT license' in a README file
There should be an OSI approved license included in the repository. Common licenses such as those listed on http://choosealicense.com are preferred. Note there should be an actual license file present in the repository not just a reference to the license.