[@Altered Tundra]
That's all to do with site encryption.

A few years ago Mahz did a change where he HTTPS the site to allow for better security but I think it was only really done on a surface level for the log ins and such. It's not anything to be too concerned with as you're not doing any sensitive transactions as HTTPS is mostly reserved for social media, email, and moreso banking.

I'd also go through and do a clean up of your history/temporary files too as there could be a cookie from a Google ad which is sending off information as well. Most of the time they're harmless, but targeted ads are a thing and that will trigger the security screener in your browser.

There's also add-ons/plug-ins you can get too like "HTTP Everywhere" for Firefox which will force an encryption on all sites. If you're not using one you can always download one of those as an added security measure