It didn't seem to be particularly linty, in my recollection. The exhaust was from the middle rear of the backsplash (you can see a knockout on the right side which I'm guessing is that round panel). There was a spring-loaded grille on the center of the backsplash, under which (for a vented installation) was a blanking plate. I remember that blanking plate had some printing on it. If you removed the blanking plate, you could slip a lint filter in for an unvented installation (the lint filter size was roughly like that generation Kenmore...squarish). You did not use both the blanking plate and the lint filter. I seem to recall only a 3" duct, not a 4". There was an intake lint filter behind the toeboard (pleated wire mesh) which never seemed to have much effect. The dryer had some sort of ignition system (no pilot light). Grandma got rid of it in about 1982 or so (I was late teens) for a Maytag rectangular door model. It was definitely bigger than my mother's 1965 Kenmore, with a bigger drum (although I believe the drum was a little shallow).