Description of the need
My understanding is that the overall goal of this issue to make it easier for contrib modules to add additional workflow states to revisions/versions than those provided by Backdrop CMS core.
The idea is to make it easier for contrib to add states such as "needs review," "deleted," "pending approval," or whatever states are needed for their custom workflows.
I would love to have someone rewrite or add to this summary of that issue. Please, feel free to review #1475 for more information, noting that much of that issue became focused on the narrower issue of Forward Revisions.
I don't know, there might be ideas here: #1475