Odd place for A/C leak?
So this past week, I thought my A/C started going out when I got nothing but warm air when on "A/C" or "MAX A/C". I was looking around for a possible leak when I felt cold air coming out from the area I have the arrow pointed to in the picture below. I pushed the spongy material around a little bit then suddenly the piping on the a/c accumulator got ice cold which told me it was working again. I felt the air inside, and sure enough it works again. I think I stopped the leak temporarily but i'm sure it'll come back in the future. First, where could the leak be coming from specifically, and second, where does that pipe lead to?
(Note: I had refrigerant lines, compressor and accumulator replaced at the end of summer in 2010 as well as a new belt 3 months ago)
2004 ford f250 6.0