“X-Content-Type-Options” not recognized by Mozilla Observatory

Hi there,

I just started with your plugin which I really like, thanks!
Using the plugin and the the Mozilla Observatory I could increase the grade from F to B.
Unfortunately it looks like enabling X-Content-Type-Options is not recognized from M.Observatoy.
Searching in the support forum I found a rather old entry.
It says the the option is only added to the delivery of the main HTML page but not to all pages and it could be fixed in a future version.
Is this still something which could be implemented or is there anything I can change in my WordPress instance?

Thank you!