Beej

WordPress 3.0+ is great. It shows you your uploaded header images. 
It’s too bad it doesn’t let you delete them as well! 
The answer is here with a simple yet extremely useful little plugin called Delete Custom Header. 
Unlike WP’s “Remove Header” button, this plugin completely removes the header image data 
from the database and the files from the server.
For themes with a header option, like Twenty Ten, Twenty Eleven, etc.

Delete Custom Header

Delete uploaded header images and remove them from the database.

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.

Delete Custom Header vs HTTP Headers