Using IE 9 or less, I'm getting a JS error "Object is required" on line 1, position 137 in stub.js.
The script stops and the
StackExchange object does not get initialized, so later there are "Object does not support this property or method" on calls to
StackExchange.init etc. Basically nothing JS-related works.
The root of the error is this chunk of code:
atob() is defined only starting at IE10. See here.