You’re asking if a binary SynthDef can be decompiled into the original source code. That’s completely impossible in every sense.
Someone very clever might be able to figure out a way to write some kind of source code that would produce the same arrangement of unit generators. But I don’t recall hearing of anyone actually doing it. I’d be happy to be wrong about that, though.
What the OP wants is to save a binary scsyndef file, and then do some process on the binary file to recover the original source code, character for character, to be able to edit it.
… which is a very complicated way to approach something that can already be done in a simple, direct way (by saving the source code).
What the OP wants is to save a binary scsyndef file, and then do some process on the binary file to recover the original source code, character for character, to be able to edit it.