DIY floor pans.
If water comes in and it never drys it will wick through the jute padding and spread all over. It typically doesnt make it to the rear pans but can if your leak(s) are bad enough or the car is sitting for a long time.
I have been chasing a ghost leak on my 73 dart sport for a year. I have found several leaks but its still getting in somewhere. I probably wont find the real leak until I get this stripped and on the rotiserie. I ordered the one piece floor pan for it. Both of my fronts are totally shot.