Unfortunately the article doesn't contain any link to the AgStack Foundation itself, so here it is: https://agstack.org/
My basic understanding is that on one side you have companies who want to sponsor open source tech they depend on, and on the other side you have open source developement teams who would like to be supported; the Foundation facilitates interaction between these 2 sides.
"The AgStack Foundation will not engage in building software applications but will instead focus on the software infrastructure (tools, frameworks, and models) that will be needed to build, manage and run applications by the members and users"