I did the same in FreeCAD. Just a simple:
1. Extract the zip to step.
2. Open in FreeCAD.
3. Delete the connectors (there are three of them, each with just some pins for some reason).
4. Export.
5. Zip up again and post.
Creating the screenshot and typing this post is more work then the actual deletion of the header.
A possible thing left, is that it has the LCD, which has a red PCB on itself, and there is another green PCB with nearly the same size. I just left both of them in the file.
I've been using FreeCAD for quite some years now. It's growing slowly in capability and user friendlyness, but it still has some way to go before a V1.0 release. And of course, together with it's Open Source nature, there is no way any company can ever hold my data hostage to extort (more) money or force me into the mist (cloud) with perpetual monthly subscription fees.