See which TLS version is in use
# look for something like
# * SSL connection using TLSv1.3 ...
curl -vI https://foobarTest if a site supports HTTP/2
curl -I --http2 https://foobarShow response header & body
curl --include https://somehostShow only response header
curl --head https://somehost
curl -I https://somehostAdd request headers
curl --header "X-MyHeader: 123" --header "X-AnotherHeader: foo" https://somehost