This means that if you want to disable a plugin you can open the DBPF file in a hex editor and change the first byte to something other than 44 (in Hexadecimal) (D) and the game will not load the plugin, but you will still be able to edit it in the reader (saving the disabled plugin with the reader will not re enable it, to re enable you must change the first byte back to 44 (hexadecimal)).