It's using HTTPS - and while I haven't actually tried to MitM it, I suspect that since it's served from Mozilla domain, the certificate must be pinned. But you

It's using HTTPS - and while I haven't actually tried to MitM it, I suspect that since it's served from Mozilla domain, the certificate must be pinned. But you're right - it may be not simple to do (or maybe I'm mistaken here) but it's certainly possible (Firefox is FOSS, so as a last resort measure it can be modified to ignore any pins). Thanks for the suggestion.