This policy controls the treatment for mixed content (HTTP content in HTTPS sites) in the browser.
If the policy is set to true or unset, audio and video mixed content will be autoupgraded to HTTPS (i.e. the URL will be rewritten as HTTPS, without a fallback if the resource is not available over HTTPS) and a 'Not Secure' warning will be shown in the URL bar for image mixed content.
If the policy is set to false, autoupgrades will be disabled for audio and video, and no warning will be shown for images.
This policy does not affect other types of mixed content other than audio, video, and images.
This policy will no longer take effect starting in Google Chrome 84.