Yeah, uh...apparently someone hasn't caught that we're working with GBA and DS games here. Still, similar principles apply. A .ZST is a ZSNES savestate; the format has changed over time, but since it's well-documented, there are many tools that let you open up a .ZST and poke around the contents of the SNES' memory at the instant the file was saved. Emulators such as VBA and NO$GBA let you cut out the middlemen endemic to SNES hacking and view memory directly: GBA and DS hacking is actually in some ways easier than SNES hacking.

In SnowBro's defense, I don't think he actually cared if anyone used his programs, he just wanted them to work. I once asked him why he never actually released any hacks with all the level editors he was making and he pretty much said that he thought ROM hacking was "stupid."