Actually I was originally going to add "so that is why you will see it frequently on projects related to those technologies," just to give some background and link it all together (e.g. the cited example is hosted on the backbone site).

But yeah, it also gives it some star power and instant credibility, and I wanted to highlight jashkenas for his significant contributions. (As a side note I don't currently use any of them, I prefer Angular and vanilla JS syntax.)