SecurityHeaders.io Missing Headers Help

[Graemezee]

Somebody Put My Site into SecurityHeaders.io and it is now on the hall of shame

I am trying to understand how I can rectify them and whether or not they will break my site Appreciate any help or directions to how to add these missing headers to an existing joomla site

Strict-Transport-Security
HTTP Strict Transport Security is an excellent feature to support on your site and strengthens your implementation of TLS by getting the User Agent to enforce the use of HTTPS. Recommended value "strict-transport-security: max-age=31536000; includeSubDomains".

Content-Security-Policy
Content Security Policy is an effective measure to protect your site from XSS attacks. By whitelisting sources of approved content, you can prevent the browser from loading malicious assets.

X-Frame-Options
X-Frame-Options tells the browser whether you want to allow your site to be framed or not. By preventing a browser from framing your site you can defend against attacks like clickjacking. Recommended value "x-frame-options: SAMEORIGIN".

X-XSS-Protection
X-XSS-Protection sets the configuration for the cross-site scripting filter built into most browsers. Recommended value "X-XSS-Protection: 1; mode=block".
X-Content-Type-Options X-Content-Type-Options stops a browser from trying to MIME-sniff the content type and forces it to stick with the declared content-type. The only valid value for this header is "X-Content-Type-Options: nosniff".

Referrer-Policy
Referrer Policy is a new header that allows a site to control how much information the browser includes with navigations away from a document and should be set by all sites.

[Graemezee]

Ok, I have now researched this, I kind of understand what it is and crucially, I now know how to implement it on a site. It is through a time-consuming effort.

I understand why it is beneficial to want your site to conform to the Content Security Policy
Other than the obvious security benefits of deploying CSP, After years of convincing clients to use Joomla, because it's more secure than other CMS 's I am wondering how to justify this procedure.

I suppose I am asking are there any commercial advantages to deploying CSP and having an A Rating ie
for an Average Joomla site Or Are there any potential downside to not deploying CSP

Finally how many people design and produce a website deploying CSP as standard I would be interested in your comments