1.3.0 — Jan. 11, 2012 Removed AMD (RequireJS) support from Underscore. If you\'d like to use Underscore with RequireJS, you can load it as a normal script, w
Jeremy gave his reasoning in the comments of the commit:
Yep. Not supporting a particular script loader will definitely make it easier for all of them to work properly.
I apologize for merging the support in the first place.
He also tweeted a bit more on the change (link from a later comment):
… because AMD support is breaking regular Underscore embeds on pages that also happen to use Require.js …