For some reason, the AMD modules from the js.arcgis.com CDN do not appear to be cached and I've been unable to determine why. Local AMD modules are caching fine:
Status Code:200 OK
Cookie:rclg0=en; __unam=f220af1-14499213906-3dc5afe-11; esri_auth=[removed by author]
Referer: [removed by author]
User-Agent:Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/37.0.2062.120 Safari/537.36
I would suspect this is from the Cache-Control: max-age=0 header, but I have no idea what would be setting that and why.