In MSVS, why must I include EntityFramework.SqlServer to get EF 6 support in MySql (no replies)

By default, when I install the EntityFramework, it automatically adds two references:

EntityFramework
EntityFramework.SqlServer

Then, if create a mysql EF 6 ADO.NET Entity Model, it works.

However, if I delete the SqlServer reference and re-add the entiy, it then limits me to EF 5.

Just looking for an explanation as to why this is so. It was frustrating to find this problem while trying to create a "pure" MySql based project.

Thanks, Chris