The intent is to manage the TOSA spec as an open source project and we’re actively encouraging other vendors and individuals to participate in the specification’s development. It’s all quite embryonic at the moment, so very little exists formally at present - but that is the intent.
If anyone is interested in helping define the TOSA specification and the future direction it takes, please do reach out (message myself, sjarus, etc or post on the mlplatform.org Discourse). We want to get to a project which works for as many people as possible and right now we only know what a few (albeit important) vendors want.