It was my pellet vent, and my roofline is pretty high and that's where capped. I have a three season room that has a roof midway through run and was able to remove section midway after disassembling midway to that point.
Sounds like you got lucky. Every time I clean the pellet liner in our 25 foot chimney I spend a few extra minutes putting a small wrap of duct tape around each and every connection. Yes, it does take me extra time (probably less than 10 minutes) But, it saves me from doing what you did when I get distracted by the dog, cat, kids, wife, TV, or whatever. I've got no interest in getting up on the roof and pulling the cap to push a stuck brush back down.