Command filter

[Sebastian]

It seems that it can be down a command filter "application/vnd.cups-command" for maintenance and configuration purposes.
I would like to make the one for my printer but I have read it is just a plane/text file with a list of available commands. In that case where should it be the code for that commands.
¿Are there any example of command filter like the ones for the raster filters?
¿Any other clue?