I think they were referring to the 3rd party add-ons that provide unlicenced sources. Granted, those add-ons are likely open-source too, so it's a matter of doi

I think they were referring to the 3rd party add-ons that provide unlicenced sources. Granted, those add-ons are likely open-source too, so it's a matter of doing your homework or having a source or curator that you trust.