How to manually test to see if HSTS is enabled on a web server
~$ curl -s -D- https://owasp.org | grep -i strict-transport-security:
Strict-Transport-Security: max-age=31536000
Strict-Transport-Security: max-age=31536000
https://owasp.org/www-project-web-security-testing-guide/latest/4-Web_Application_Security_Testing/02-Configuration_and_Deployment_Management_Testing/07-Test_HTTP_Strict_Transport_Security