This is a remix of an ESP-32 compatible breadboard holder from DieHardMetalHead. 

The .3mf file is scaled up to 100.55%, which is where my printer needs to be for dimensional accuracy. It's a tight fit, so your mileage may vary. Clip off the little connectors on the breadboards before trying to insert them. I also included holes in the back to make it easier to pop the breadboards out.