Allowing preconnects when remote resource loading is disabled would be a serious security fail, so I hope that's not what Thunderbird is doing. Suppose I initia

Allowing preconnects when remote resource loading is disabled would be a serious security fail, so I hope that's not what Thunderbird is doing. Suppose I initiated a connection to long-unique-identifier.mysite.com? At minimum this could be used for tracking beacons, possibly even to exfiltrate data.