Reading the texts again it seems it&#x27;s more like they heavily encourage that license when used commercially (fair enough) and not saying it&#x27;s mandatory (which contradicts the MIT license). Looks like I&#x27;m not the only one who is confused: <a href="https:&#x2F;&#x2F;github.com&#x2F;usablica&#x2F;intro.js&#x2F;issues&#x2F;573" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;usablica&#x2F;intro.js&#x2F;issues&#x2F;573</a>