HOST=$(curl https://token.actions.githubusercontent.com/.well-known/openid-configuration | jq -r '.jwks_uri | split("/")[2]')

echo | openssl s_client -servername $HOST -showcerts -connect $HOST:443 2> /dev/null \
  | sed -n -e '/BEGIN/h' -e '/BEGIN/,/END/H' -e '$x' -e '$p' | tail +2 \
  | openssl x509 -fingerprint -noout \
  | sed -e "s/.*=//" -e "s/://g" \
  | tr "ABCDEF" "abcdef"