Accessing nested MetaData read from YAML file

[laurentkempe]

I am working on porting my blog to 😍 Statiq from Hexo. I started to work on a Statiq theme which would port partially hexo-theme-tranquilpeak.

My theme defines a themesettings.yml, copy pasted from my hexo _config.yml which is correctly read thanks to Statiq ThemeManager.

In my .cshtml file I can read nested properties which would output its value fa fa-home

@Metadata["sidebar:menu:home:icon"]

Now, I would like to get access to nested properties for another file _config.yml which is added using

await Bootstrapper
    .Factory
    .CreateWeb(args)
    .BuildConfiguration(builder => builder.AddYamlFile("_config.yml", optional: false, reloadOnChange: true))
    .RunAsync();

I am struggling to get access to nested properties in _config.yml, e.g.

@Metadata["external_link:enable"]

would output a critical error

My config file is read correctly which I can control with optional: false and I can see that the top property is also read.

I can read the nested property by doing the following

@{
    var external_link = (IMetadata)Metadata["external_link"];
}

@external_link["enable"]

What I don't understand is why it works to access nested properties of themesettings.yml and not in my _config.yml?