A missing semicolon is preventing "minifying" of prototype.js using jsmin and consequently the asset packager plugin.
Index: actionpack/lib/action_view/helpers/javascripts/prototype.js
===================================================================
--- actionpack/lib/action_view/helpers/javascripts/prototype.js (revision 6010)
+++ actionpack/lib/action_view/helpers/javascripts/prototype.js (working copy)
@@ -843,7 +843,7 @@
}
params = Hash.toQueryString(params);
- if (params && /Konqueror|Safari|KHTML/.test(navigator.userAgent)) params += '&_='
+ if (params && /Konqueror|Safari|KHTML/.test(navigator.userAgent)) params += '&_=';
// when GET, append parameters to URL
if (this.method == 'get' && params)