Max Harmony

Add NSA Header uses a list of keywords known to be sensitive to mass spying operations. It randomly selects a few of those keywords with each page request and includes them in an NSA-Keywords HTTP header. This introduces useless information to mass spying operations, reducing their effectiveness.
It is recommended that this be used only on WordPress sites that are only accessible via TLS.

Add NSA Header

Add NSA Header adds an NSA-Keywords HTTP header to reduce the effectiveness of mass spying operations.

Dimitar Ivanov

HTTP Headers gives your control over the http headers returned by your blog or website.
Headers supported by HTTP Headers includes:
<ul>
<li>Access-Control-Allow-Origin</li>
<li>Access-Control-Allow-Credentials</li>
<li>Access-Control-Max-Age</li>
<li>Access-Control-Allow-Methods</li>
<li>Access-Control-Allow-Headers</li>
<li>Access-Control-Expose-Headers</li>
<li>Age </li>
<li>Content-Security-Policy</li>
<li>Content-Security-Policy-Report-Only</li>
<li>Cache-Control</li>
<li>Clear-Site-Data</li>
<li>Connection</li>
<li>Content-Encoding</li>
<li>Content-Type</li>
<li>Cross-Origin-Embedder-Policy</li>
<li>Cross-Origin-Opener-Policy</li>
<li>Cross-Origin-Resource-Policy</li>
<li>Expect-CT</li>
<li>Expires</li>
<li>Feature-Policy</li>
<li>NEL</li>
<li>Permissions-Policy</li>
<li>Pragma</li>
<li>P3P</li>
<li>Referrer-Policy</li>
<li>Report-To</li>
<li>Strict-Transport-Security</li>
<li>Timing-Allow-Origin</li>
<li>Vary</li>
<li>WWW-Authenticate</li>
<li>X-Content-Type-Options</li>
<li>X-DNS-Prefetch-Control</li>
<li>X-Download-Options</li>
<li>X-Frame-Options</li>
<li>X-Permitted-Cross-Domain-Policies</li>
<li>X-Powered-By</li>
<li>X-Robots-Tag</li>
<li>X-UA-Compatible</li>
<li>X-XSS-Protection</li>
</ul>

HTTP Headers

Great plugin with a huge amount of settings. Despite the complexity of the setup, the developers have added comments with links to full help. It helps a lot that the comments are also translated into Russian.
After setting up the plugin, be sure to check both the functionality of the site and the speed indicators. Some settings may slow down the site loading speed.

Wonderful

HTTP Headers adds CORS & security HTTP headers to your website.

Add NSA Header vs HTTP Headers