Connected Workspaces functionality is documented at https://developer.opentext.com/apis/061923d5-1fc8-4f78-a6e2-6d276a3fcfe0/Connected-Workspaces-REST-API
Looks like I didn't find it previously for a few reasons - at the most basic, the search box on the APIs page (https://developer.opentext.com/apis ) does not index the contents of the various APIs, it only filters the product names in the catalog. Similarly the documentation search facility at knowledge.opentext.com doesn't surface any API specifications. However, the search box at the very top of the site (https://developer.opentext.com/ ) does index the full content of the APIs specification documents. Additionally, and this speaks to my inexperience, the Connected Workspaces API is presented as a different product from Content Server within the API catalog (presumably due to feature licensing issues?) so I didn't spend enough time rooting around manually either.