Configuring X-Download-Options

There are two settings:

Configuration Resulting header
enabled=”false” None
enabled=”true” X-Download-Options: noopen

Register the middleware in the OWIN startup class:

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
    ...

    app.UseStaticFiles();

    app.UseXDownloadOptions();

    app.UseMvc(...);
}

Or as an MVC attribute (which defaults to true):

[XDownloadOptions]
[XDownloadOptions(Enabled = false)]

The header is omitted for redirects.