Digging into a specific theme, I have discovered that a file named metadata.html.twig is supposed to be included in base.html.twig but seems to not exist in the partials folder.
As this theme was originally composed by Grav team members (such as @rhuk), I crosspost here in case some of them can check this issue or if anybody else can tell me what this file is suppose to do in such a theme.
Thanks.