As the author has forgotten to add a detailed usage listing (or I can't find it), I wonder if anyone knows anything about the command-line options accepted by the FernFlower decompiler application.
You can find an online version here: http://www.reversed-java.com/fernflower/ I'm trying to enable/disable all these flags that are present on that webpage.
The actual command-line JAR can be found here: https://github.com/Bukkit/Bukkit-MinecraftServer
Many thanks Nik
Answer
As the author has forgotten to add a detailed usage listing
No, I haven't :) See readme.txt in your jar for the full documentation.