the clues are in the audioin/audioout submodules of fx13, you need to send to fx13-$1-in where $1 is the name of the module. also if you want to strip it out of the other patches, you’ll probably want to alter the UI.
C&G have behind the scenes been doing some great work on modularising there patches… I look forward to see where they are going with them
anyway, if you dig into one of the C&G new patches its pretty straightforward, and nicely structured… and a bonus reward for persevering is you will be able to create all sorts of interesting new combs of C&G patches, once you understand the basics.
( p.s. i will say the fx13 is a little more complex that some of the other patches, because of the way it allows the subpatches to be turned on/off to saye cpu… but for the most part, patchers can ignore these complications)