Why does it not?
https://launchpad.net/~team-xbmc/+archive/ppa ppa:team-xbmc/ppa <<-- Final XBMC releases only
https://launchpad.net/~team-xbmc/+archive/unstable ppa:team-xbmc/unstable <<-- Current Gotham Development Beta -> RC (when Final release gets moved to ppa above)
https://launchpad.net/~team-xbmc/+archive/xbmc-nightly ppa:team-xbmc/xbmc-nightly <<-- Master Nightly builds
On the ppa:team-xbmc/ppa there was no Trusty and so on when 12.3 was released so there is no builds for Frodo in trusty and likely wont ever be (officially)
Why libs and stuff get built, is for same reason stated, I suspect that because these packages were available post Frodo or were built for after the fact or copied form other ppa), and hence will build for all available Ubuntu Distros, makes perfect sense as depends on packager and ppa.
In fact it says for libcec "Copied from ubuntu trusty in Pulse by Wolfgang Schupp" so was copied from
https://launchpad.net/~pulse-eight/+archive/pulse to all other xbmc ppas whatever other packagers do is their decision,
You probably know this, but ill say it anyway.
Packager "Person A" build package xyz for all current Ubuntu distros on ppa Y, Then Packager "Person B" ges and copies packages xyz from ppa Y to his own ppa Z to either all distros or to specified ditros the "Person B" specifies at copy time. Person B can also choose to either rebuild packages or just to copy the results or "person A",
Now "Person B" on his ppa Z only had his own packages xxx for Ubuntu distros 1,2 and 3 but the packages xyz copied for ppa Y were built for Ubuntu distros 1,2,3,4,5,6 -- this results in what you see in many ppas and in this case this one.
