As we roll out the TLS 1.0 and 1.1 deprecation, sites that don't support TLS 1.2
will show the neterror page. This adds a box to that page that shows in this
specific case. That box explains what is going on and gives an option to
re-enable TLS 1.0.
As mentioned, this will show alongside an option to reset TLS-related
preferences if any overrides are active.
Hitting the button will set the new pref to 'true' and reload the page.
Once the override is engaged, the option won't show, but that option to reset
preferences will show (as this is a TLS-related preference).
The intent is to remove this affordance in March 2020 as we formally move to
having TLS 1.2 the minimum version. All going to plan, this will only affect
prerelease channels, though anyone who has tweaked security.tls.version.* could
also see this.
Differential Revision: https://phabricator.services.mozilla.com/D45799
f34a2ef4fb
