@User (@User): One slightly insidious aspect of the behavior is that a cell doesn't have to be read from LEF to be considered abstract; it just needs to point to a GDS file, which tells magic that the contents of the GDS file are what the cell really is, not what shows up in the magic view. I prefer not to make abstract cells that look like full layouts, but occasionally it comes in handy. My goal is to get magic to exactly reproduce any GDS file it reads. That seems like a simple thing, but magic is designed to automatically generate a lot of layers from rules rather than read and write them verbatim, and so it's hard to get magic to read in GDS and write out the exact same GDS. Hence the use of pointers to GDS files for known-good vendor library cells.