What is the editions map in the book workspace?

It's the overview of your book across languages. The first row is the original; every row below is a translated edition. Each small square is one chapter: green means translated, dark means not yet, red means the translation of that chapter failed (hover to see why), and an amber ring means you have edited the original chapter since it was translated — click the refresh icon on that row to re-translate only the changed chapters. A ♪ mark in a square means that chapter has an audiobook rendered in that language, and the headphones icon jumps straight to the Audio studio for that edition.