Retrieve HTTP Headers from URL.

Returns the real mime type of an image file.

Retrieve list of mime types and file extensions.

Get the header information to prevent caching.

Retrieve original referer that was posted, if it exists.

Retrieves unvalidated referer from ‘_wp_http_referer’ or HTTP referer.

Retrieve referer from ‘_wp_http_referer’ or HTTP referer.

Gets the URL to learn more about updating the site to use HTTPS.

Returns the default annotation for the web hosting altering the “Update PHP” page URL.

Gets the URL to learn more about updating the PHP version the site is running on.