pred_

Depending a bit on which browser we are talking about, passive mixed content (such as images) will typically be allowed through on default settings, while only active mixed content is blocked.

Meanwhile, the chromium preload list just passed 10.000 domains. Things are moving forwards.

https://twitter.com/lgarron/status/718242465782853633

All that site returns here is

    FCC Federal Communications Commission
    Security Violation

    Your request looked malicious and has been blocked.
    You can use your browser's Back button to return to the previous page.
    If you have questions, please contact the FCC at 1-888-225-5322
    If you think that you have reached this page due to an error on our part, please contact let us know.

As far as I can tell, the website can not be used to browse all certificates directly; when the number was at 500k, the site would consistently time out when trying to fetch the oldest ~250k.

Is the raw data available somewhere?

On a completely different and off-topic note, as someone who would normally just handle my certificate needs by piping together 10 openssl commands, your ACME client is super handy!