Hi,
just check for m3u8 extensions to find all quality links and to make it easy to find them use Adblock AddOn.Just check some other topics so biezom did post already many examples about that with pictures.
Code:
http://ga.video.cdn.pbs.org/videos/wqed-pittsburgh/566b879c-1b60-4020-bb38-be06815c7410/55481/hd-mezzanine-16x9/sq-hill-tunnels-16x9-hls-800k.m3u8
you can also use livestreamer to download the file instead to watch it or both etc.
greetz