Snippets » Firefox » Register domains as secure contexts
If you want a domain to be treated as a secure context (and get access to all the sensitive JavaScript APIs that are gated behind that arbitrary designation), you can add it to the pref:
dom.securecontext.allowlist
Unfortunately due to a bug, Firefox will then try to upgrade any resource requests to HTTPS, and you’ll probably end up with no images. The workaround for now is to disable upgrades entirely:
security.mixed_content.upgrade_display_content false