I am not the author.
https://github.com/galdor/github-license-observer
https://addons.mozilla.org/en-GB/android/addon/github-license-observer/
This is a cool little addon to help you tell, at a glance, if the repository you're browsing on github has an open source license license.
Especially relevant nowadays given the trend to convert previously OS repos to non-OS licenses as a business model (eg Akka or Terraform.)
Wait, MIT isn’t open source!?
Created an issue on the repo: https://github.com/galdor/github-license-observer/issues/5
It is: https://opensource.org/license/mit/
It's most probably a bug in the addon. Best to report it on the repo's issue tracker: https://github.com/galdor/github-license-observer/issues