Self-signed certificates & Firefox are broken?

[pmeenan]

Firefox disabled any way to ignore cert errors as a security measure so it no longer works for Firefox (at this point it may be Chrome and IE-only). The legacy Windows agent used to force it by intercepting the API calls internal to Firefox but that is no longer possible with the cross-platform agent.

The only way to do it now for Firefox is to run a private instance of WPT and install the certs (or a custom root) on the test machines so they see the self-signed certs as valid.