There's a whole bunch of descriptions starting at ED/6400. Items, spells, lores, and blitzes are here. The pointers for them are after the descriptions themselves. The SwdTech and Blitz descriptions are at CF/FC00, with the pointers starting at CF/FF9E. You'll need a table file (
ZD has them, so does
Lord J's site), and a competent hex editor. I suggest
WindHex32. One of a few flaws it has is lack of smart DTE typing. That's ok though, the descriptions can't use DTE so that won't be a worry. One thing that is a worry though, is that I think all of these pointers are relative (though whoever coded bank C3 made it easy enough to change to absolute, but that's another subject).
Now, for these addresses I gave. I'm almost certain this will confuse you, since it's "teh assembly." It's really a lot more simple than some (including myself many moons ago) make it out to be. To get to a file address, you need to figure out what the CPU address (ED/6400, etc) is using. There are two "types," both dubbed by the community, but in reality I don't think they have names. They are LoROM, and HiROM. LoROM is basically like an extended NES in terms of mapping and addressing, with some optimizations. This is a gross generalization, and I know there are better descriptions. FF6, however, uses HiROM, which for all intents and purposes is much simpler. To calculate file address, take the CPU address and subtract 0xC00000 from it. Example: ED/6400 - C0/0000 = 0x2D6400. There's one other factor though, and that's the header. If your rom has a header (it'll likely be 0x200 bytes of many zeros), then you need to add 0x200 to that result to get to your file address.
Another alternative you can consider is this. The next official version of FF3usME will have support for editing these descriptions. If you wish, you can wait until that's out, whenever that may be. However, if you wish to explore this option, we'll be here to give some help and advise. If you need some clarification on anything, feel free to ask.