I'm afraid my question is a no-brainer for almost everybody, but I can't find the answer. I can't find it using Google, StackOverflow or by examaning the code generated by Features.
How can I store the default theme of a site in a feature? Do I need Strongarm? What would be the name of the variable?
(It feels like a duplicate of Drupal Features include Theme, but we're four years further now)