Okay, not that type of airbag! Rather a new and improved crash reporting application. This will replace the similar but rather out-dated ‘Talkback’ feature most users are accustom to when a Mozilla application crashes. Like Talkback, Airbag is completely voluntary, you can provided as much (or as little) information as you would prefer to disclose. But keep in mind the more information your willing to provide the better the chances of getting the bug fixed that caused the application to crash in the first place. More technical information can be found over at mozilla links Blog.
