Dont have a photo sorry, but I’m thinking you might be referring to the cowl anti ice system.
And that is why I love aviation, the simplest things sometimes.
Exhaust shroud showing cowl heater tube. Photo Credit: eBay
Graphic, Cowl Anti-Ice System. Photo Credit: I wish I could give credit, but I don't know where this photo originally came from. It has been a part of every PT6 PowerPoint I remember seeing for the last 15 years.