Romnames and tags also were pretty cryptic to me for a while. I still don't know what means some tags from all of them.
@Ronflaix
Tbh the only ones of any real concern are the ones for what region (usually capital letters, like F for French, U for US, E for European - I think S is Spanish), ! Meaning "known good dump", h for romhack, and t for translation patched. I think b might be "bad dump" but it also could be "bootleg"
@Nine ah, according to this[0], it means having a trainer and T a translation. :O
@Ronflaix
Oh nice! I think I said lower case t before because some translation patch websites aren't following rom codes properly or something.
@Nine oh yeah, that's the wonder issue with that kind of standard : many sets will be off the rules on some points.