CONSOLE ERROR: line 58: Mixed Content: The page at 'https://web-platform.test:8444/mixed-content/xhr-request/http-csp/cross-origin-http/top-level/keep-scheme-redirect/blockable/opt-in-blocks.https.html' was loaded over HTTPS, but requested an insecure XMLHttpRequest endpoint 'http://www1.web-platform.test:8001/mixed-content/generic/expect.py?redirection=keep-scheme-redirect&action=purge&key=136d08cd-63b5-4a23-8441-aeda2b69861a&path=%2Fmixed-content&content_type=application/json'. This request has been blocked; the content must be served over HTTPS.
