See here for the initial board stack up and features. Things haven't changed a lot between the initial draft and now. What has changed is via stitching/fencing, and the use of 2.54 mm header pins instead of the 1.00 mm header pins. I hate making a bigger board than I need for components, but it is what it is. 1.00 mm header pins aren't cheap or easy to find.
KiCad files posted to my GitHub. Link is on the main project page. If you like this design block and want to use it in any of your projects, you may want to wait until I get this assembled and tested.