The Decoders node displays all decoders currently installed in the system. For more information on how to configure a decoder please refer to Modules/Decoder. As you can see in the picture below the Decoders node lists all the decoders currently installed. In the right hand pane you can see the number of invocations, the source block, i.e. the block that triggers the decoder execution. And finally a description which is the doc string that can be specified with the decoder definition.
Upon expanding a particular decoder node in the left pane you will see the output blocks this particular decoder generates. From here on you have the same properties as the Blocks node.
Right clicking on any decoder node in the right hand pane will pop up a menu that allows you to enable/disable the decoder or delete it altogether. Keep in mind, if you assign the decoder to a variable that you maintain, for example in a Python script, the decoder will not be removed until you release this variable. The delete operation only releases the internal reference that is held by the Explorer. If the decoder is a histogram decoder you can additionally set some of the histogram decoder properties here.
You can select multiple decoders and invoke the operation on all the selected decoders at once.