I saw that Facebook like open-source software a lot. Is there some webmaster-specific reason why don't they use jQuery or another javascript library? Is that because jQuery/another js library has a lot[1] of kilobytes? Or another reason?[1] I know it's only about 50kb, but you have to consider that's Facebook, a lot of traffic
Is there serious reason why big company like Facebook or Google don't use front-end libraries such as jQuery?
google;javascript;facebook