The Workspace entity was first seen in the contrib module Multiversion on 1st June 2014. Back then the entity type was called "Content repository", it was renamed to "Workspace" in September 2014.
On 22nd Febuary 2016 the Workspace module was created, which built upon the Multiversion module.
The Workflow Initiative was announced in Dries' keynote DrupalCon New Orleans.
Today the Workspace module landed in Drupal core as a new experimental module. This module is very different from the contrib Workspace module. It has no dependencies and now actually has a lot in common with the Drupal 7 module CPS.
Please give the module a try, join us in the issue queue, and help us get Workspace module beta ready for 8.6.0-alpha1 in just over 2 months time.
It's amazing how you succeeded not to say a word about what this module is about... but hey, we know it's whole history!
I am not a developer, but I am interested in possibly useful Drupal modules and functionality. Workspace sounds like something useful, but I can't really discern from your introduction what it does. Could you please include some information on what Workspace does and for what purpose it woudl be useful?
Thanks in advance for your information.