Are you getting an error message trying to connect to the site? Could you share the URL of the page where you have the problem? In order to bypass the spam link moderation queue, you can insert a space before the top level domain. For example:

https://www.treasurydirect .gov/indiv/myaccount/myaccount.htm

(The Open Account link doesn't load for me in either Firefox or Edge at the moment.)

I can't get a universal download link so I suggest you go to mozilla. org and proceed from there.