@User I tried to generate <<checkpaint>> into my generated .mag files according to the documentation, but when I open the file with magic, it still says DRC=0 until I do a DRC update (perhaps due to hierarchical designs?). It would be nice to be able to generate .mag files with a way to indicate that the whole file would need to be checked, without having to calculate the bounding-box of the cell.

Maybe setting the timestamp to zero will force DRC to run?

Yes! That's it. Zero helps.

It doesn't, really. There's just a line somewhere in the code that forces it to run checks on any file with a zero timestamp.