[shonenknifefan1]

It looks like the CAD file formats are specified here:

https://github.com/usnationalarchives/digital-preservation/b...

which includes X3D, STEP, PDF/E, U3D, PRC

[tpmx]

AutoCAD R10+ (1989), Microstation CAD, DesignCAD and IGES are listed here:

https://www.archives.gov/preservation/digital-preservation/l...