Hehe. In Australia for some reason routing to repositories is shockingly slow. I run apt-cacher-ng on my VPS in Arizona to boost my speed. It works quite well with 300kbps instead of 20kbps.

sources.list.d/hildon-application-manager-list is a dynamic file created by app manager when you click "install". It's generated from this variant-catalogue reference file that lives somewhere else. I guess "man find" will my friend in this case.