yearofmoo/ngAnimate-animate.css — pull request #2 by fsobczak (2013-08-29 11:59:21+00:00)
Title: added .fade-in for compatibility with Bootstrap

Not sure if that's the best way to enable .fade with bootstrap, here's the name collision:

in bootstrap/less/component-animations.less:
.fade {
opacity: 0;
.transition(opacity .15s linear);
&.in {
opacity: 1;
}
}