But it was able to successfully ping my running Steam Client. The page works like an acid test; if it's clean, you're clean. If it finds something, it says what and the port.
Real fun times is the fact that -on Linux machines- something like this will cause Steam to freeze and even crash certain games just by visiting the page: https://wybiral.github.io/steam-block/
Chrome v75.0.3770.100: "Mixed Content: The page at 'https://wybiral.github.io/localtoast/' was loaded over HTTPS, but requested an insecure image 'http://192.168.1.254/images/att_globe_logo.png'. This content should also be served over HTTPS."
Firefox v69.0b4: "Loading mixed (insecure) display content “http://fritz.box/css/rd/images/fritzLogo.svg” on a secure page"
Edge v44.18362.1.0: "SEC7137: [Mixed-Content] The origin 'https://wybiral.github.io' was loaded in a secure context and loaded an optionally blockable insecure image resource at 'http://fritz.box/css/rd/images/fritzLogo.svg'."