MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
I'll add the slot for the Camera ribbon as that is a quick change. I cannot state when it will be done as I live in central Florida and we have a hurricane headed our way.
To answer your question, these holes are for a Raspberry Pi 3b+ and others of that form factor. I currently have no intentions modifying this design to include a RPi4 as that would consist of considerable work on my part and is outside the scope of this project.
However, that being said, from just briefly looking at the spec sheet, it appears you could fit a 4 without changes if you simply mirror all the parts. However, I don't know how the cabling will work with the controller board on the left. You would also have much longer run of the power cable. Another option would be cut the entire RPi slot into a single large rectangular opening. Finally I see no reason the existing DC-DC converter will not work. The 4B runs off of 5V 3A. The DC-DC converters I linked have a maximum power output of 3A.