Pressing the 'Optimized content gallery' tab from my Settings brings me here:
Which displays the ordinary site & theme instead of admin panel, and returns this message:
Sorry, we can't find the content you're looking for at this URL. Please try selecting a menu item from above or to the side of this message to get where you'd like to go.
Looking at the old plugin you've forked this from I'm very excited to see how this turns out though! :)