My overbaked rosemary olive oil sourdough

your bread doesn't look overbaked to me.  When I was just starting baking, I used to bake my breads to a  light brown color, but then I began reading books, especially Breads from La Brea Bakery.  I learned about caramelization of sugars to develop flavor in the crust.  When I tried to bake them longer and really started to appreciate the difference in the taste of the crust, and how the crust helps flavor the crumb.  It is really really good baked dark, IMO that is.  Many people think I overbake my bread, but I like it just fine.  I hope you ate the bread and did not throw it away.  If you tried it, did you like the crust?

look at the third question down on this link, it says a little about dark crusts.  though looking at the website, they need to take her advice, because the breads there don't have the dark crust that are pictured in her book.

http://www.labreabakery.com/bread_faqs.aspx

but the bread might be a little overproofed. It looks like the score marks are the same color as the rest of the crust. This means that the loaf did not have as much oven spring as if it had been slightly less proofed. All of that, though, doesn't take away from the beautiful loaf of bread you made.

I guess the coloration of the crust could also be because you didn't score it deep enough. I think dmsnyder has a great tutorial on scoring. you should give it a look.

In any case, your loaf looks great. I hope you enjoyed it.