To make your IPv6-only HTTPS services available via IPv4, simply:
A record to 185.220.100.168.
Currently, this will only proxy HTTPS connections.
In the mean time, connection attempts via HTTP will be
answered with a temporary redirect (302) to HTTPS.
HTTP connections will NOT YET be proxied.
This server is running snid in nat46 mode.
Client IPv4s are embedded in the lowest 4 bytes of the request.