I pinged engineering and they pointed me to a cool FAQ wiki.
Unfortunately it is not possible to provide the IP range. Here is the
clip from the FAQ wiki. Is there a Runtime IP range that customers can
enable?No, we don't share IP ranges with customers for two
reasons:Security Best Practices - Runtime is a multi tenant environment
in which all customers share the same IPsOperation Agility - Runtime is
being deployed to multiple regions and/or clouds and the list of IPs can
change at any time.If ...