@shanselman @foone if it’s compressed it’ll have a utility to show you compression stats, like DBLSPACE.EXE. So I’d run that. But not necessarily anything in config.sys because dblspace.bin loads earlier. Mem will also show the driver chewing up RAM.
Or you could image it and try and mount the image on Linux.
If you would boot an old MS-DOS computer and the filesystem was still working it would not matter since you would just see all the boot messages flash over the screen and it would just work as it used to. Most of the compression packages just created a hidden system file that was loaded as a virtual file system.
Answering the second question. Yes, the device drivers would all be listed in the config.sys.