CONSOLE ERROR: Mixed Content: The page at 'https://web-platform.test:8444/mixed-content/img-tag/http-csp/same-host-http/top-level/swap-scheme-redirect/optionally-blockable/opt-in-blocks.https.html' was loaded over HTTPS, but requested an insecure image 'http://web-platform.test:8001/mixed-content/generic/expect.py?redirection=swap-scheme-redirect&action=purge&key=cf0007fc-ec89-441b-89d9-5f821d38af3a&path=%2Fmixed-content&content_type=image/png'. This request has been blocked; the content must be served over HTTPS.
