The version of a page (or blog post) visible to workflow participants.
The 'draft version' of a page (or blog post) is the version that has been edited and subject to a workflow. It refers to the fact that there is some difference in content between a published version and its current state. Or, if the page was created and part of an automatic workflow, it reflects its 'pre-published' (also draft) state.
The draft version is only visible by workflow participants.