Javascript errors when proxies strip headers

[LindsayHill]

Some corporate firewall/proxy devices such as Watchguard strip some HTTP headers, such as Access-Control-Allow-Origin:

This means that exchange.stackstorm.org is unusable for those users. They will see errors such as this:

bundle.js:26 GET https://index.stackstorm.org/v1/index.json?_=1494592700909 403 (Forbidden) 
send @ bundle.js:26 
ajax @ bundle.js:25 
componentDidMount @ bundle.js:48 
notifyAll @ bundle.js:45 
close @ bundle.js:67 
closeAll @ bundle.js:26 
perform @ bundle.js:26 
s @ bundle.js:45 
perform @ bundle.js:26 
batchedUpdates @ bundle.js:67 
i @ bundle.js:1 
_renderNewRootComponent @ bundle.js:45 
_renderSubtreeIntoContainer @ bundle.js:45 
render @ bundle.js:45 
(anonymous) @ bundle.js:68 
t @ bundle.js:1 
(anonymous) @ bundle.js:1 
(anonymous) @ bundle.js:1 
bundle.js:26 GET https://index.stackstorm.org/v1/index.json?_=1494592700909 403 (Forbidden) 
send @ bundle.js:26 
ajax @ bundle.js:25 
componentDidMount @ bundle.js:48 
notifyAll @ bundle.js:45 
close @ bundle.js:67 
closeAll @ bundle.js:26 
perform @ bundle.js:26 
s @ bundle.js:45 
perform @ bundle.js:26 
batchedUpdates @ bundle.js:67 
i @ bundle.js:1 
_renderNewRootComponent @ bundle.js:45 
_renderSubtreeIntoContainer @ bundle.js:45 
render @ bundle.js:45 
(anonymous) @ bundle.js:68 
t @ bundle.js:1 
(anonymous) @ bundle.js:1 
(anonymous) @ bundle.js:1 
exchange.stackstorm.org/:1 XMLHttpRequest cannot load https://index.stackstorm.org/v1/index.json?_=1494592700909. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'https://exchange.stackstorm.org' is therefore not allowed access. The response had HTTP status code 403. 
bundle.js:48 error 
error @ bundle.js:48 
u @ bundle.js:24 
fireWith @ bundle.js:24 
n @ bundle.js:25 
(anonymous) @ bundle.js:26

Don't think there's any easy way around this.