This is absolutely without regard to method, technoiogy, markup, standards, or responsible parties.
Those can come later, but this is to enumerate the steps in the PG workflow (although "flow" is a stretch in some cases) in order to provide scope for any discussion of PG workflow per Greg Newby's post.
These have to be accomplished one way or another in order for a book to become an ebook in the PG catalog, and support multiple format output and ongoing refinement and error correction.
Some can be simultaneous and there's overlap. Some may be provided by external sources (e.g. images.) Participants include volunteers, PG, and customers.
1. Choose a book to digitize.
2. Collect and record metadata, and confirm Public Domain status.
2. Obtain images of all the pages.
3. Produce text with OCR.
4. Refine the text to match the OCR.
5. Locate and mark significant artifacts in the text.
6. Submit package of text(s) and images to PG.
7. PG review and post to catalog.
9. Select layout and format for desired device or application.
10. Select or create layout and format for text and artifacts.
11. Issue ebook per spec (possibly including production.)
12. Identify errors or other revisions to text.
13. Locate and describe revisions.
14. Submit revision to PG.
15. Back to step 7 to validate and apply revision.
There are obvious definitions to be provided, including metadata, refine, location and mark, significant artifacts, package, etc. etc.
Don