Hi teachers,

This dialogue was part of an interview between a BBC reporter(A) and the inventor of BitTorrent Bram Cohen(B) in a TV show:

B: We've never been sued, so that's good.
A: Why is that, do you think?
B: Because we are technology venders. And also...
A: So you are just the plumbing basically.
B: Yeah, and I've also never been like rah-rah piracy...

I don't quite understand what "the plumbing" mean here and I don't see anything to do with plumbing in the context, but since this is what I heard rather than read so if I misheard something please help to point it out.

Thanks in advance!