For the non-videographer, B-Roll is video / film shot to be part of an opening sequence or perhaps to be used to cover edits / transitions during a piece. The audio of B-Roll is generally unimportant.
I was recent at the Mozilla Foundation headquarters filming an interview to appear in an upcoming issue of IEEE Computer Magazine (computer.org/portal/web/computer/home) and was walking around the office filming some B-Roll before the interview and came across this scene.
Their conference rooms have names and letters. The name for the room is "BIKESHED" because it is (a) a place they use to store bikes, and (b) "Bike Shedding" refers to silly arguments that one often has in conference rooms - en.wiktionary.org/wiki/bikeshedding
The tasty triple irony is that the room is also "Conference room B" indicated by a large brushed aluminum capital "B" (as in Bikeshed and B-Roll).
Of course the shot also features a simultaneous pan/tilt/zoom/roll focus that is one of the standard features of good B-Roll. I won't claim that my camera work as the best ever as I am still working through the techniques controlling roll focus on my Sony HDR-CX560V camcorder and it was my second day of using my shiny new Sony VCT-60AV Remote Control Tripod. My camera control is OK but not stellar.
And of course the audio narration is topical as well.