On ppa.pl I mentioned a "youtube links" script for selecting file formats.

This video is available as MP4 (video+audio) only for 360p version. Youtube selector lists 360p here only. With a script you can select other formats, though they will be played by OWB, not youtube html5 player.

M4V and VP9 are video only. Audio is in a separate file - M4A, VOR, OPUS. OWB can play M4V or VP9 files fine, but for audio - only M4A works.