Follow on to using URL https://dev.twitter.com/docs/embedded-timelines to see the problem. When I use an Incongnito Browser, the widgets.js loads as expected.
It appears that normal mode and incognito mode send out fundamentally different requests:
NORMAL CHROMIUM BROWSER - NO RESPONSE
Request URL:https://platform.twitter.com/widgets.js
Request Headersview source
Accept:/
Cache-Control:max-age=0
Referer:https://dev.twitter.com/docs/embedded-timelines
User-Agent:Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/28.0.1500.71 Chrome/28.0.1500.71 Safari/537.36
INCOGNITO CHROMIUM BROWSER - GOT RESPONSE
Request URL:https://platform.twitter.com/widgets.js
Request Method:GET
Status Code:200 OK
Request Headersview source
Accept:/
Accept-Encoding:gzip,deflate,sdch
Accept-Language:en-GB,en-US;q=0.8,en;q=0.6
Connection:keep-alive
DNT:1
Host:platform.twitter.com
Referer:https://dev.twitter.com/docs/embedded-timelines
User-Agent:Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/28.0.1500.71 Chrome/28.0.1500.71 Safari/537.36