ping is synonymous with echo-request, which is largely transport agnostic.

but you're right

why 443? are you assuming ssl here? serious question, I'm not sure. But if it is, wouldn't it be hard to disregard the weight of SSL in the metric?

The code closes the connection immediately after opening a plain TCP socket, so no SSL work is done. Presumably 443 is just a convenient port to use.

tcp/443 is likely an open port on the target service (Dynamodb based on the domain name). TLS is not involved.

ICMP ECHO would be a bad choice as it is deprioritized by routers[0].

[0] https://archive.nanog.org/sites/default/files/traceroute-201...

The script connects to well known 'dynamodb.' + region_name + '.amazonaws.com' server that expects HTTPS