To inject extra meta tags into your tunrkey application create a file like this:

Views/EXT_OverridePages/__ExtraMetaTags.cshtml

Example of meta tag you want to inject:

<meta http-equiv="Content-Security-Policy" content="default-src 'self'">

If the file is found the contents is read and injected after the standard meta tags.

Use the AssetsTK strategy to inject your file into the application