Ah, I looked in the wrong place.  It's under "Removing and Installing Components"! Specifically... [URL] Interesting that all screws are flat head even when thin pan head or washer head would seem appropriate. Thanks.
Does anybody know the screw specifications for the Dell Latitude 5490 for: Back cover.  Type (known - flat) , screw diameter, length, thread / pitch.  Whoever worked on my refurb unit stripped the Philips "slot" on 2 of the screw heads of the black screws that secure the back cover.  These appear to be M2 x 7mm, pitch unknown. Hold down screw for the NVMe M.2 SSD.  What is in there is a short flat head screw, but, it appears that a washer or pan head would be better.  The installed screw appears to be a Philips M2 x 4mm*, pitch unknown.*Estimate -- I did not measure this one. Hold down screw for the SATA M.2 SSD in the WWAN slot.  (Yeah, I got the drive to work.).  Nothing was installed in the WWAN slot as I received the machine, so, not surprisingly, no screw...  It appears that a washer or pan head screw would be best.  Best guess would be that it should be a Philips M2 x 4mm*, pitch unknown.*Estimate -- Nothing there to measure.
Screw(s) specification(s) for Dell Latitude 5490