WordPress uses a CURL operation to test for SSL capability for XML-RPC. If you’re using XML-RPC but not using, then you can remove the filter. This is a small performance boost (since basically WP does a cURL GET on the https url and either 1) gets a denied message, or 2) times out, and it can take upwards of 5 seconds), but in our case it actually prevented a gateway timeout where a proxy was timing out before the cURL GET was timing out rendering XML-RPC unusable.
// Prevents WordPress from testing ssl capability on domain.com/xmlrpc.php?rsd
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