It just allows you to sign items, that's it.
Features highly customizable messages, check the config for permissions.
Commands:
/sign - sign item in your hand (in case it's not signed)
/unsign - unsign item in your hand (in case you are the owner of the sign or are in creative mode)
/sign_all - sign every item in your inventory (if possible)
/unsign_all - unsign every item in your inventory (if possible)
