[Coco] ROMPAKs

[Tony C]

 Looking through various archives, I see rompak files with the .ROM and
.CAR, and .PAK extensions.
What are the differences in these extensions?
 Also, I see roms for the RS232pak, and Ochestra 90.
Since these 2 cartridges had dedicated hardware above and beyond a ROM, what
good would these ROM images be, since they required specific hardware to
run?
(other than something for someone to dissasemble to see how these cartridges
worked)
  thanks