I think the confusion is coming from the mutiple meanings of "rom." In both cases it stands for read only memory, but in this forum it typically refers to a modded version of android os. In the game emulator world it refers to the read only memory from video games (ie the info that was originally stored in the NES cartridges) that has been decompiled and modded into a version that can run on devices other than the original game console.
It depends on what emulator your are using, I use snesoid. Get a root file explorer and look through the folder on your sdcard. Random thing: I just beat super mario world for snes, and super mario 64 for n64.