APT is said to be Advanced Package Tool (and i think wikipedia is wrong about the name… but i’m not quite sure). I don’t know if there’s a homepage. My reference point is Debian Unstable, as far as apt goes. APT is important for libept. There are a few frontends to the libapt-pkg, like apt-get, apt-cache, aptitude, synaptic and adept. I work on the last one mentioned, that’s where my interest in APT comes from. APT is a decently thought up piece of work, however, it tends to lack a bit in the code and library design departments. Whole thing is aging a bit as well.
One of primary purposes of libept is to bring APT back into line with more modern solutions (yum, smart and others). That, but not sacrificing speed and memory usage. And interfacing to other languages than python.